Log Python version in CI

.github/workflows/python-tests.yml

@@ -36,6 +36,9 @@ jobs:
       uses: actions/setup-python@v1.1.1
       with:
         python-version: ${{ matrix.python-version }}
+    - name: Log Python version
+      run: >-
+        python --version
     - name: Cache pip
       uses: actions/cache@v1
       with: