Update manim discord invite link

Author: naveen521kk

manimpango/__init__.py

@@ -27,7 +27,7 @@
 If you believe there is a greater problem,
 feel free to contact us or create an issue on GitHub:
 
-    * Discord: https://discord.gg/mMRrZQW
+    * Discord: https://www.manim.community/discord/
     * GitHub: https://github.com/ManimCommunity/ManimPango/issues
 
 Original error: {ie}