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.

(cherry picked from commit dabe2e1)

Author: devversion

.gitignore

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