[go-builder] env GOPROXY=
[!go-builder] env GOPROXY=https://proxy.golang.org

go list -m -versions go
stdout 1.20.1 # among others
stdout 1.19rc2
! stdout go1.20.1 # no go prefixes
! stdout go1.19rc2

go list -m -versions toolchain
stdout go1.20.1 # among others

	{"1.6", "1.6.1", -1},
	{"1.19", "1.19.0", 0},
	{"1.19rc1", "1.19", -1},
	{"1.20", "1.20.0", 0},
	{"1.20rc1", "1.20", -1},
	{"1.21", "1.21.0", -1},
	{"1.21", "1.21rc1", -1},
	{"1.21rc1", "1.21.0", -1},
	{"1.6", "1.19", -1},
	{"1.19", "1.19.1", -1},
	{"1.19rc1", "1.19", -1},
	{"1.19rc1", "1.19.1", -1},
	{"1.19rc1", "1.19rc2", -1},
	{"1.19.0", "1.19.1", -1},
	{"1.19rc1", "1.19.0", -1},
	{"1.19alpha3", "1.19beta2", -1},

	{"go1.19rc1", "go1.19rc2", -1},
	{"go1.19.0", "go1.19.1", -1},
	{"go1.19rc1", "go1.19.0", -1},
	{"go1.19alpha3", "go1.19beta2", -1},
	{"go1.19beta2", "go1.19rc1", -1},
	{"go1.1", "go1.99999999999999998", -1},
	{"go1.99999999999999998", "go1.99999999999999999", -1},
}

func TestLang(t *testing.T) { test1(t, langTests, "Lang", Lang) }

var langTests = []testCase1[string, string]{
	{"bad", ""},
	{"go1.2rc3", "go1.2"},
	{"go1.2.3", "go1.2"},

	{"1.6", "1.6.1", -1},
	{"1.19", "1.19.0", 0},
	{"1.19rc1", "1.19", -1},
	{"1.20", "1.20.0", 0},
	{"1.20rc1", "1.20", -1},
	{"1.21", "1.21.0", -1},
	{"1.21", "1.21rc1", -1},
	{"1.21rc1", "1.21.0", -1},
	{"1.6", "1.19", -1},
	{"1.19", "1.19.1", -1},
	{"1.19rc1", "1.19", -1},
	{"1.19rc1", "1.19.1", -1},
	{"1.19rc1", "1.19rc2", -1},
	{"1.19.0", "1.19.1", -1},
	{"1.19rc1", "1.19.0", -1},
	{"1.19alpha3", "1.19beta2", -1},

- For v1.25, Kubernetes will be using Golang 1.19, In this PR the version is updated to 1.19rc2 as GA is not yet available. ([#111254](https://github.com/kubernetes/kubernetes/pull/111254), [@dims](https://github.com/dims))