Update build

* Update to Go 1.16.
* Drop /vendor
* Update Go modules.

Signed-off-by: Ben Kochie <superq@gmail.com>

.circleci/config.yml

@@ -5,7 +5,7 @@ executors:
   # Whenever the Go version is updated here, .promu.yml should also be updated.
   golang:
     docker:
-    - image: circleci/golang:1.15
+    - image: circleci/golang:1.16
 
 jobs:
   test:

.gitignore

@@ -2,3 +2,4 @@
 .build
 .tarballs
 testoutput
+/vendor

.golangci.yml

@@ -1,6 +1,3 @@
-run:
-  modules-download-mode: vendor
-
 # Run only staticcheck for now. Additional linters will be enabled one-by-one.
 linters:
   enable:

.promu.yml

@@ -1,11 +1,11 @@
 go:
     # Whenever the Go version is updated here, .travis.yml and
     # .circle/config.yml should also be updated.
-    version: 1.15
+    version: 1.16
 repository:
     path: github.com/prometheus/promu
 build:
-    flags: -mod=vendor -a -tags 'netgo static_build'
+    flags: -a -tags 'netgo static_build'
     ldflags: |
         -s
         -X github.com/prometheus/common/version.Version={{.Version}}

go.mod

@@ -4,10 +4,10 @@ require (
 	github.com/Masterminds/semver v1.5.0
 	github.com/google/go-github/v25 v25.1.3
 	github.com/pkg/errors v0.9.1
-	github.com/prometheus/common v0.13.0
-	golang.org/x/oauth2 v0.0.0-20200107190931-bf48bf16ab8d
+	github.com/prometheus/common v0.18.0
+	golang.org/x/oauth2 v0.0.0-20210220000619-9bb904979d93
 	gopkg.in/alecthomas/kingpin.v2 v2.2.6
-	gopkg.in/yaml.v2 v2.3.0
+	gopkg.in/yaml.v2 v2.4.0
 )
 
 go 1.14