Backport of ci: Single source of truth for Go version in CI and Dockerfile into release/1.16.x#20161

zalimeni merged 1 commit intorelease/1.16.xhashicorp/consul:release/1.16.xfrom

backport/zalimeni/use-go-version-file/manual-1.16.xhashicorp/consul:backport/zalimeni/use-go-version-file/manual-1.16.xCopy head branch name to clipboard