Update checks actions workflow

Author: hackebrot

.github/workflows/run-checks.yml

@@ -1,36 +1,33 @@
 name: Run checks
+
 on: [push, pull_request]
+
 jobs:
-    tox:
-        runs-on: ubuntu-latest
-        strategy:
-            matrix:
-                environment:
-                    # Run tests with Python 3.6
-                    - "py36"
-                    # Run tests with Python 3.7
-                    - "py37"
-                    # Run code checks
-                    - "flake8"
-                    # Run static type checker
-                    - "mypy"
-                include:
-                    - environment: "py36"
-                      python: "3.6"
-                    - environment: "py37"
-                      python: "3.7"
-                    - environment: "flake8"
-                      python: "3.7"
-                    - environment: "mypy"
-                      python: "3.7"
-        container:
-            image: python:${{ matrix.python }}
-        steps:
-            - uses: actions/checkout@master
-            - name: Install tox
-              run: |
-                  python -m pip install --upgrade pip
-                  pip install tox
-            - name: Run tox
-              run: |
-                  tox -e ${{ matrix.environment }}
+  tox:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        environment: ["py36", "py37", "flake8", "mypy"]
+
+        include:
+          - environment: "py36"
+            python: "3.6"
+          - environment: "py37"
+            python: "3.7"
+          - environment: "flake8"
+            python: "3.7"
+          - environment: "mypy"
+            python: "3.7"
+
+    container:
+      image: python:${{ matrix.python }}
+
+    steps:
+      - uses: actions/checkout@master
+      - name: Install tox
+        run: |
+          python -m pip install --upgrade pip
+          python -m pip install tox
+      - name: Run tox
+        run: |
+          tox -e ${{ matrix.environment }}