Only run the weekly stats update for ArmDeveloperEcosystem/arm-learning-paths repository.

This commit prevents the update from running on the (many) clones.
I suspect the stats update has very little benefits on the clones and
could even be considered an annoyance as it introduces stats update
commits.

Author: Arnaud-de-Grandmaison-ARM

.github/workflows/weekly_stats_update.yml

@@ -17,6 +17,7 @@ on:
 jobs:
   # This workflow contains a single job
   update_stats:
+    if: github.repository == 'ArmDeveloperEcosystem/arm-learning-paths'
     runs-on: ubuntu-latest
     steps:
       - name: Check out current repo