Add automatic type checking workflow for all future changes

.github/workflows/lint.yml

@@ -0,0 +1,24 @@
+name: Lint Check
+
+on: [push, pull_request]
+
+jobs:
+  mypy:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Set up Python
+        uses: actions/setup-python@v2
+        with:
+          python-version: '3.x'
+
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          pip install mypy
+
+      - name: Run mypy
+        run: |
+          mypy guibot