Post mypy results to PR review

This uses reviewdog, similar to on the main Matplotlib repo.

Author: QuLogic

.github/workflows/mypy.yml

@@ -22,15 +22,27 @@ jobs:
       - name: Set up Python
         uses: actions/setup-python@v4
 
+      - name: Set up reviewdog
+        run: |
+          mkdir -p "$HOME/bin"
+          curl -sfL \
+            https://github.com/reviewdog/reviewdog/raw/master/install.sh | \
+              sh -s -- -b "$HOME/bin"
+          echo "$HOME/bin" >> $GITHUB_PATH
+
       - name: Install Python dependencies
         run: |
           python -m pip install --upgrade pip
           python -m pip install --upgrade mypy
 
       - name: Install cycler
         run: |
-          python -m pip install --no-deps .
+          python -m pip install --no-deps -e .
 
       - name: Run mypy
+        env:
+          REVIEWDOG_GITHUB_API_TOKEN: ${{ secrets.GITHUB_TOKEN }}
         run: |
-          mypy cycler test_cycler.py
+          mypy cycler test_cycler.py | \
+            reviewdog -f=mypy -name=mypy \
+              -tee -reporter=github-check -filter-mode nofilter