feat: add labels to go_binary

[sagikazarmark]

Would it make sense to add pass_env as well?

I'd use it in a setup like this:

go_binary(
    name = "todo",
    srcs = glob(["*.go"], exclude = ["*_test.go"]),
    definitions = {
        "main.version": "${VERSION:-" + git_branch() + "}",
        "main.commitHash": git_commit()[0:8],
        "main.buildDate": f'$(date -u -d "@{timestamp}" "{date_fmt}" 2>/dev/null || date -u -r "{timestamp}" "{date_fmt}" 2>/dev/null || date -u "{date_fmt}")',
    },
    #labels = ["binary"],
    #pass_env = ["VERSION"],
    #trimpath = True,
    visibility = ["PUBLIC"],
)

[Tatskaari]

I think the reason we didn't was mostly because we didn't see the use case. I'm not against adding more of these things to go_binary if they're useful.