This looks particularly obnoxious for the owners plugin, because it's
actually two plugins with a common library in the same repo. Other
plugins are much cleaner to deal with (hence the default for
overlayPluginCmd).
Change-Id: Ibb9588c8a29b63e8509436fcbb70054e89349712
Reviewed-on: https://cl.tvl.fyi/c/depot/+/1461
Tested-by: BuildkiteCI
Reviewed-by: glittershark <grfn@gws.fyi>
