ci: fix mypy if condition

.github/workflows/ci.yml

@@ -38,7 +38,7 @@ jobs:
           python -m pip install --upgrade pip
           pip install flake8 pytest pytest-mock mypy types-protobuf
           pip install --use-pep517 -r requirements.txt
-          mypy --install-types --non-interactive
+          mypy --install-types --non-interactive *.py
       - name: Lint with flake8
         run: |
           # stop the build if there are Python syntax errors or undefined names
@@ -48,6 +48,6 @@ jobs:
       - name: Type checking with mypy
         run: |
           mypy --strict *.py
-        if: matrix.python-version == "3.x"
+        if: matrix.python-version == '3.x'
       - name: Test with pytest
         run: pytest