Move HOOK_VERSION into the githook package and export it as
githook.HookVersion, so tailscale/corp can reference it via
the shared-code bump instead of having to bump HOOK_VERSION
by hand.
New launcher.sh composes the wanted version from 2 sources:
the shared HOOK_VERSION and an optional repo local version,
misc/git_hook/HOOK_VERSION, for repo-specific config bumps.
Updates tailscale/corp#40381
Change-Id: I7cf16889ba53cb564cc2df7dfd7588748f542c55
Signed-off-by: Fernando Serboncini <fserb@tailscale.com>
Fernando Serboncini