.githooks/pre-push: Use /usr/bin/env sh instead of /usr/bin/sh

While /usr/bin/sh runs fine on linux, it is better to use env to lookup sh from path, as macOS did not have sh in /usr/bin (It was in /bin).

Author: amartyasinha

.githooks/pre-push

@@ -1,4 +1,4 @@
-#!/usr/bin/sh
+#!/usr/bin/env sh
 
 set -e