fix submodule post-checkout hook

Author: evertlammerts

.githooks/post-checkout

@@ -1,6 +1,3 @@
-#!/bin/sh
-if [ "$3" = "1" ]; then
-    echo "Updating submodules..."
-    git submodule update --init --recursive
-fi
+#!/usr/bin/env bash
 
+git submodule update --init --recursive