Add Gnome 47 support

All that is needed is adding 47 to metadata.json

metadata.json

@@ -4,7 +4,7 @@
   "gettext-domain": "forge",
   "uuid": "[email protected]",
   "settings-schema": "org.gnome.shell.extensions.forge",
-  "shell-version": ["45", "46"],
+  "shell-version": ["45", "46", "47"],
   "session-modes": ["user", "unlock-dialog"],
   "version": "1.2-alpha",
   "url": "https://github.com/forge-ext/forge"