ci: store failure logs as artifact in coverage.yml

It looks like the step for storing the artifact with logs after workflow
failures was missed. Now it is added.

NO_DOC=ci
NO_CHANGELOG=ci
NO_TEST=ci

(cherry picked from commit 27f4ba7a)

.github/workflows/coverage.yml

@@ -67,9 +67,17 @@ jobs:
         uses: ./.github/actions/send-telegram-notify
         if: failure()
 
-      - name: Collect artifacts
+      - name: Collect coverage info
         uses: actions/upload-artifact@v2
         with:
-          name: failure-logs
+          name: coverage
           retention-days: 21
           path: ./coverage.info
+
+      - name: Collect failure logs
+        uses: actions/upload-artifact@v2
+        if: failure()
+        with:
+          name: failure-logs
+          retention-days: 21
+          path: ${{ env.VARDIR }}/artifacts