build: exlude .history folder in gitignore

This folder is commonly used by extensions for keeping local
file histories. Similar to how it's excluded in the FW repo.

Author: devversion

.gitignore

@@ -47,6 +47,7 @@ testem.log
 /.git
 /.firebase
 /.bazelrc.user
+/.history/
 *.log
 .ng-dev.user*
 .husky/_