update postmoogle source code url

roles/custom/matrix-bot-postmoogle/defaults/main.yml

@@ -1,6 +1,6 @@
 ---
 # postmoogle is an email to matrix bot
-# Project source code URL: https://gitlab.com/etke.cc/postmoogle
+# Project source code URL: https://github.com/etkecc/postmoogle
 
 matrix_bot_postmoogle_enabled: true