dev-cmd/bump: add --no-fork switch

Signed-off-by: Patrick Linnane <patrick@linnane.io>

Library/Homebrew/dev-cmd/bump.rb

@@ -37,6 +37,8 @@ module Homebrew
              description: "Check only casks."
       switch "--installed",
              description: "Check formulae and casks that are currently installed."
+      switch "--no-fork",
+             description: "Don't try to fork the repository."
       switch "--open-pr",
              description: "Open a pull request for the new version if none have been opened yet."
       flag   "--limit=",
@@ -509,6 +511,8 @@ module Homebrew
       "--message=Created by `brew bump`",
     ]
 
+    bump_cask_pr_args << "--no-fork" if args.no_fork?
+
     system HOMEBREW_BREW_FILE, *bump_cask_pr_args
   end