[ci] Retry running test suite on failure

Author: pandafy

.github/workflows/ci.yml

@@ -72,13 +72,16 @@ jobs:
 
       - name: Test
         if: ${{ !cancelled() && steps.auto_install_upgrade.conclusion == 'success' }}
-        # The auto-install script installs docker-openwisp by default in
-        # /opt/openwisp/docker-openwisp. To ensure the test runs correctly
-        # and environment variables remain intact, it is essential to
-        # execute the test from this directory.
-        run: |
-          (make develop-pythontests && make stop)
-        working-directory: /opt/openwisp/docker-openwisp
+        uses: nick-fields/retry@v3.0.2
+        with:
+          timeout_minutes: 20
+          max_attempts: 5
+          # The auto-install script installs docker-openwisp by default in
+          # /opt/openwisp/docker-openwisp. To ensure the test runs correctly
+          # and environment variables remain intact, it is essential to
+          # execute the test from this directory.
+          command: make develop-pythontests && make stop
+          working_directory: /opt/openwisp/docker-openwisp
         env:
           SELENIUM_HEADLESS: 1