Add GitHub Actions workflow

.github/workflows/check.yml

@@ -0,0 +1,20 @@
+
+name: Check
+
+on:
+  push:
+  pull_request:
+
+jobs:
+  check:
+    runs-on: "ubuntu-latest"
+    name: "check"
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-python@v5
+        with:
+          python-version: "3.12"
+
+      - name: "Run checks"
+        run: |
+          python ./check.py