Upgrade go to 1.19 in Dockerfile

[andrei-21]

Currently docker build fails with:

$ docker build .
...
github.com/lightningnetwork/lnd/discovery
# github.com/lightningnetwork/lnd/discovery
/go/pkg/mod/github.com/lightningnetwork/lnd@v0.16.0-beta/discovery/gossiper.go:644:15: undefined: atomic.Uint64
note: module requires Go 1.19
make: *** [Makefile:55: build] Error 2
The command '/bin/sh -c apk add --no-cache --update alpine-sdk     git     make     gcc &&  cd /go/src/github.com/lightninglabs/faraday &&  make &&  make install' returned a non-zero code: 2

Pull Request Checklist

• Update MinLndVersion if your PR uses new RPC methods or fields of lnd.

[guggero]

Thanks, LGTM 🎉

[ellemouton]

LGTM!