Replace outdated terminology in README
Replace outdated terminology in README

jenkinsci/git-plugin,martinda/git-plugin,MarkEWaite/git-plugin,jenkinsci/git-plugin,MarkEWaite/git-plugin,martinda/git-plugin,martinda/git-plugin,MarkEWaite/git-plugin,MarkEWaite/git-plugin,jenkinsci/git-plugin,jenkinsci/git-plugin