Remove generate-release-notes-v7 script
Remove generate-release-notes-v7 script

There is no more BUILD_VERSION_V7 file so we should use
generate-release-notes instead.

Co-authored-by: Sebastian Vidrio <68ba84219e4e2d7d15fed3ed668bd2821314e420@pivotal.io>

cloudfoundry/cli,cloudfoundry/cli,cloudfoundry/cli