.gitconfig: Remove the destructive undopush alias

.gitconfig

@@ -23,8 +23,6 @@
 	credit = "!f() { git commit --amend --author \"$1 <$2>\" -C HEAD; }; f"
 	# Interactive rebase with the given number of latest commits
 	reb = "!r() { git rebase -i HEAD~$1; }; r"
-	# Undo a `git push`
-	undopush = push -f origin HEAD^:master
 
 [apply]
 	# Detect whitespace errors when applying a patch