fix(deps): update dependency nodebb-plugin-composer-default to v6.3.21 (#8119)

Co-authored-by: WhiteSource Renovate <renovatebot@gmail.com>

install/package.json

@@ -79,7 +79,7 @@
         "mousetrap": "^1.6.1",
         "mubsub-nbb": "^1.5.1",
         "nconf": "^0.10.0",
-        "nodebb-plugin-composer-default": "6.3.20",
+        "nodebb-plugin-composer-default": "6.3.21",
         "nodebb-plugin-dbsearch": "4.0.7",
         "nodebb-plugin-emoji": "^3.0.0",
         "nodebb-plugin-emoji-android": "2.0.0",