buildGoPackage: update Go to version 1.12

[kalbasit]

Motivation for this change

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nox --run "nox-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Determined the impact on package closure size (by running nix path-info -S before and after)
• Assured whether relevant documentation is up to date
• Fits CONTRIBUTING.md.

---

[kalbasit]

I'm running nox review pr 56927 on my server to verify all ~500+ build correctly. I do not wish to hammer ofborg with this change.

Building the following packages

linuxkit helmfile gohai pprof gdrive terraform-providers.atlas hologram
terraform-providers.matchbox nsq prometheus-json-exporter metricbeat pond
packetbeat docker-proxy envsubst terraform-providers.nsxt shadowfox dgraph kops
terraform-providers.powerdns sift browserpass perkeep gllvm buildkite-agent
gopass lxd wal-g peco openshift cni mage terraform-providers.tencentcloud
terraform-providers.panos gucci datadog-trace-agent terraform-providers.datadog
gitAndTools.git-bug gotop terraform-providers.oraclepaas quicktemplate golint
terraform-providers.triton deisctl kubecfg prometheus-consul-exporter coredns
prometheus-mesos-exporter prometheus heartbeat5 websocketd heptio-ark dex-oidc
godef gitea kompose terraform-providers.arukas scaleway-cli
terraform-providers.ignition terraform-providers.brightbox coyim
deepin.deepin-metacity drone nginx-sso flannel gocode mynewt-newt lego dbmate
terraform-providers.helm mautrix-whatsapp bosun unconvert ipfs gotests
oci-image-tool terraform-providers.cloudstack librarian-puppet-go
terraform-providers.postgresql altcoins.go-ethereum boohu docker-machine-kvm
prometheus-mysqld-exporter git-lfs1 terraform-providers.spotinst
terraform-providers.kubernetes cloud-print-connector hecate marathonctl
terraform-providers.rabbitmq cayley prometheus-nginx-exporter gotools cri-tools
errcheck qr-filetransfer webhook journalbeat browsh packetbeat5 terraform-docs
skydns maligned corgi certstrap datadog-process-agent sops
terraform-providers.google-beta grafana_reporter mustache-go
azure-storage-azcopy confd gx vale terraform-providers.dyn glide clair go2nix
trezord uchiwa cide qsyncthingtray cloud-sql-proxy gosec kubicorn
terraform-providers.tfe dep timescaledb-parallel-copy
terraform-providers.cloudflare scollector dnscrypt-proxy2 stern
terraform-providers.mysql minikube terraform-providers.segment
terraform-providers.skytap git-sizer go-motion terraform-providers.ns1 goconvey
ipfs-migrator morty heapster s3gof3r ssm-agent envconsul madonctl certmgr
prometheus-minio-exporter simplehttp2server keybase go-protobuf
terraform-providers.nutanix xmonad-log cockroachdb
terraform-providers.oneandone kubernetes-helm terraform-providers.null buildah
prometheus-statsd-bridge gogetdoc todolist terraform-providers.rancher
container-linux-config-transpiler prometheus-bind-exporter
gitAndTools.git-annex-remote-rclone moby certmgr-selfsigned overmind kexpand
prometheus-dovecot-exporter ngrok-1 terraform-providers.azuread envdir aptly
hcloud amass minio-client syncthing-relay drive packet gnatsd pcstat
terraform-providers.packet mirrorbits delve terraform-providers.dnsimple desync
go-symbols fac terraform-providers.archive terraform-providers.librato
terraform-providers.cloudscale terraform-providers.local restic
amazon-ecr-credential-helper matterbridge matterircd meme
terraform-providers.http gocyclo tychus terraform-providers.pagerduty
terraform-providers.consul terraform-providers.gitlab
prometheus-surfboard-exporter prometheus-unifi-exporter docker-ls
terraform-providers.acme slack-term k6 python37Packages.syncthing-gtk
vimPlugins.youcompleteme antibody mmark skopeo terraform-providers.heroku etcd
heartbeat filebeat5 easyjson prometheus-blackbox-exporter
terraform-providers.linode syncthing-discovery codesearch
terraform-providers.cobbler gitAndTools.git-annex-remote-b2
terraform-providers.nixos prometheus-haproxy-exporter podman
terraform-providers.vcd skaffold pup wuzz kubeval todoist oauth2_proxy
terraform-providers.vault gitaly terraform-providers.newrelic udocker
nvidia-docker filebeat influxdb tewisay ycmd prometheus-statsd-exporter
terraform-providers.rundeck go-langserver deepin.deepin-desktop-schemas govc
kubectl telegraf phraseapp-client go-pup jd pgmetrics kbfs
python27Packages.syncthing-gtk skydi ve mqtt-bench pgcenter lazygit nixops-dns
go-repo-root teleport minishift deepin.dde-api morph
terraform-providers.azurestack notary wtf circleci-cli ineffassign c14
mesos-dns tegola gocode-gomod go-jira terraform-providers.fastly mongodb-tools
awless gitAndTools.grv metricbeat5 terraform-providers.alicloud hydron gotty
deepin.deepin-wm impl prometheus_2 restic-rest-server kt dep2nix xmloscopy
packer terraform-providers.icinga2 deis curl_unix_socket convoy kubernetes
json2hcl keybase-go kubectx mm subfinder hetzner-kube terraform-providers.nomad
terraform-providers.template terraform-providers.scaleway fsql
prometheus-rabbitmq-exporter terraform-providers.gandi ejson grobi gocryptfs
docker-distribution prometheus-dnsmasq-exporter pachyderm
terraform-providers.opentelekomcloud docker-machine-kvm2 archiver
terraform-provider-nixos terraform-providers.flexibleengine go-junit-report
ctop terraform-providers.docker reflex go-bindata cli53 terraform_plugins_test
cfssl platinum-searcher joker altcoins.go-ethereum-classic autospotting
deadcode gogs gosu kail kind terraform-providers.rightscale go-md2man
terraform-providers.opc terraform-full systrayhelper goa argo dashing
prometheus-postfix-exporter mattermost go-mtpfs gawp etcdctl kontemplate goklp
vimPlugins.YouCompleteMe ua pipework massren ksonnet prom2json aws-env
nats-streaming-server terraform-providers.external terraform-providers.ovh
kube-prompt caddy interfacer go-2fa terraform-providers.softlayer
terraform-providers.influxdb terraform-providers.ibm filegive
deepin.deepin-desktop-base azure-vhd-utils mop terraform-providers.github dive
saml2aws goconst terraf orm-providers.aws reftools doctl ecs-agent
terraform-providers.hedvig gitAndTools.lab terraform-providers.bigip
terraform-providers.digitalocean gron gopkgs terraform-providers.oci textql
prometheus-snmp-exporter terraform-providers.azurerm gitlab-runner
terraform_0_11-full aminal runc deepin.deepin-wallpapers iamy iferr minify
exercism teleconsole buildkite-agent3 vgo2nix asmfmt aws-iam-authenticator
mmake traefik kapacitor terraform-provider-ibm nomad gitAndTools.hub
syncthing-cli mailhog lf jmespath go-check gomuks noti direnv drone-cli ghq
terraform-providers.profitbricks ical2org terraform-providers.google vultr
consul-template blsd terraform-providers.logicmonitor chezmoi gauge go-tools jp
terraform-providers.hcloud wego terraform-providers.selvpc docker-gc
gitAndTools.git-appraise git-lfs terraform-providers.mailgun
terraform-providers.ultradns meguca httplab docker-machine go-bindata-assetfs
singularity deepin.dde-daemon terraform-providers.secret
terraform-providers.openstack manul terraform-providers.netlify
terraform-providers.logentries kube-router containerd aws-vault
fscrypt-experimental prometheus-fritzbox-exporter styx assh
prometheus-openvpn-exporter elvish vault syncthing-tray hugo journalbeat6
diskrsync terraform-inventory bazel-buildtools terraform-providers.statuscake
distrobuilder gcsfuse mtail prometheus-alertmanager docker grpcurl
python37Packages.jupyter-repo2docker golangci-lint toxiproxy leaps syncthing
ipget terragrunt yaml2json kube-aws ipfs-cluster pet compile-daemon richgo
gh-ost rclone terraform-providers.libvirt bettercap govers consul-alerts
terraform hivemind localtime terraform-providers.chef terraform-providers.dns
gomodifytags minio prometheus-collectd-exporter terraform-providers.tls elfinfo
terraform-providers.huaweicloud terraform-providers.dme vimPlugins.vim-go
terraform-providers.telefonicaopencloud terraform-provider-libvirt
terraform-providers.grafana terraform_0_12 terraform-providers.ucloud
terraform-providers.random vndr interlock powerline-go miniflux ws i3cat
grafana hyperledger-fabric loccount terraform-providers.terraform
terraform-providers.runscope terraform-providers.bitbucket aws-rotate-key up
btops systemd-journal2gelf cloudfoundry-cli terraform-providers.vsphere consul
shfmt terminal-parrot xmpp-client xurls hound serfdom micro
prometheus-node-exporter holochain-go go-dependency-manager datadog-agent
terraform-providers.circonus livepeer prometheus-pushgateway cointop goimports
fzf gometalinter git-town terraform-providers.clc terraform-providers.opsgenie
govendor oh echoip docker-credential-gcr aws-okta go-upower-notify kustomize
jid gx-go prometheus-varnish-exporter gox go-outline gotags go-sct glock 

[kalbasit]

@vcunat I need help merging this to staging.

[vcunat]

I'm not a go person, but it seems good. Upstream claims a very high level of compatibility.

Going through staging should give a little time to fix (unlikely) "disasters", so I don't think we need to wait now for more contributors to notice.