adding auth token

Author: deusebio

.github/workflows/on_pull_request.yaml

@@ -58,6 +58,8 @@ jobs:
     - id: tests-integration
       name: Run Integration Tests
       shell: bash
+      env:
+        CHARMCRAFT_AUTH: ${{ secrets.CHARMHUB_TOKEN }}
       run: |
         pip install pyyaml
         sudo snap install charmcraft --classic