ci: ensure sass is not updated, for now

Because of twbs/bootstrap#34051, the sass package is currently set to "~1.32.11".

Also see https://stackoverflow.com/questions/67675422/deprecation-warning-in-bootstrap-scss

This serves as a reminder, so that we do not accidentally bump sass to the latest version for now, until this issue is resolved

.github/renovate.json

@@ -26,6 +26,10 @@
       "updateTypes": ["patch", "pin", "digest"],
       "automerge": true,
       "semanticCommitType": "ci"
+    },
+    {
+      "matchPackageNames": ["sass"],
+      "enabled": false
     }
   ],
   "timezone": "Africa/Lusaka",