I thought our versioning scheme would make go.mod include a commit hash
even on stable builds. I was wrong. Fortunately, the rest of this code
wants anything that 'git rev-parse' understands (to convert it into a full
git hash), and tags qualify.
Signed-off-by: David Anderson <danderson@tailscale.com>
With this change, you can collect version info from either a git
checkout of the tailscale.com Go module (this repo), or a git
checkout of a repo that imports the tailscale.com Go module.
Signed-off-by: David Anderson <danderson@tailscale.com>