Add ci checks.

.github/workflows/checks.yml

@@ -0,0 +1,30 @@
+name: Checks
+
+on:
+  pull_request:
+  push:
+    branches:
+      - stable
+      - dev
+
+jobs:
+  mypy:
+    runs-on: ubuntu-latest
+
+    steps:
+    - name: Checkout repository
+      uses: actions/checkout@v2
+
+    - name: Set up Python
+      uses: actions/setup-python@v2
+      with:
+        python-version: 3.10
+
+    - name: Install dependencies
+      run: |
+        python -m pip install --upgrade pip
+        pip install -r .github/workflows/requirements.txt
+
+    - name: Run MyPy
+      run: |
+        python -m mypy .

.github/workflows/requirements.txt

@@ -0,0 +1,3 @@
+requests ~= 2.28.0
+graphviz ~= 0.20.1
+mypy ~= 1.7.0

requirements.txt

@@ -1,2 +0,0 @@
-requests ~= 2.28.0
-graphviz ~= 0.20.1