github_packages: add comment for image-spec pin
github_packages: add comment for image-spec pin

Homebrew/brew,nandub/brew,JCount/brew,Homebrew/brew,MikeMcQuaid/brew,JCount/brew,MikeMcQuaid/brew,MikeMcQuaid/brew,MikeMcQuaid/brew,Homebrew/brew,JCount/brew,nandub/brew,nandub/brew,nandub/brew,Homebrew/brew,JCount/brew