Add problem matcher to "Check Python" workflow

This will cause error messages to be surfaced in the workflow run summary and logs, making it easier to discover the
cause of a workflow run failure.

Author: per1234

.github/workflows/check-python-task.yml

@@ -53,7 +53,10 @@ jobs:
           version: 3.x
 
       - name: Run flake8
-        run: task python:lint
+        uses: liskin/gh-problem-matcher-wrap@v1
+        with:
+          linters: flake8
+          run: task python:lint
 
   formatting:
     runs-on: ubuntu-latest