fix: set github discussions of forum link

Author: datamweb

composer.json

@@ -81,8 +81,7 @@
         "test": "phpunit"
     },
     "support": {
-        "forum": "https://forum.codeigniter.com",
-        "chat": "https://github.com/codeigniter4/shield/discussions",
+        "forum": "https://github.com/codeigniter4/shield/discussions",
         "slack": "https://codeigniterchat.slack.com",
         "source": "https://github.com/codeigniter4/shield",
         "issues": "https://github.com/codeigniter4/shield/issues",