tailscale: update version stamping for 1.38
Current versions are reporting a build version error:
# tailscale version
1.38.3-ERR-BuildInfo
go version: go1.20.2
This started happening with 1.38.0, which changed the version stamping and updated build_dist.sh.
I think this would update the version flags to match:
VERSIONFLAGS="
-X tailscale.com/version.shortStamp=$pkgver
-X tailscale.com/version.longStamp=$pkgver-AlpineLinux
-X tailscale.com/version.gitCommitStamp=AlpineLinux
"