chore(CI): Added job to clean up old workflow runs to main workflow

- Deletes runs more than 15 days old
- Retains last 5 runs of each workflow, regardless of age

.github/workflows/main.yml

@@ -51,3 +51,13 @@ jobs:
     needs: RunUnityTests
     uses: ./.github/workflows/Semantic.yml
     secrets: inherit
+
+  DeleteOldWorkflowRuns:
+    name: Delete Old Workflow Runs
+    runs-on: ubuntu-latest
+    steps:
+      - name: Delete workflow runs
+        uses: Mattraks/delete-workflow-runs@v2
+        with:
+          retain_days: 15       # Delete runs older than 15 days
+          keep_minimum_runs: 5  # Keep the last 5 runs