add tmate session after running test suite

Author: ylebre

.github/workflows/solid-tests-suites.yml

@@ -152,3 +152,6 @@ jobs:
             --env COOKIE_BOB="$COOKIE_thirdparty" \
             --env-file ./env-vars-testers.list \
             ${{ matrix.test }}
+
+      - name: Setup tmate session
+        uses: mxschmitt/action-tmate@v3