Try using setup-python

.forgejo/workflows/lint.yaml

@@ -6,20 +6,16 @@ name: Lint
 jobs:
   lint:
     name: MyPy
-    runs-on: docker
+    runs-on: ubuntu-22.04
     steps:
-      - name: Checkout
+      - name: Checkout the code
         uses: actions/checkout@v4
-      # TODO: Replace with working action
+      - name: Set up the Python toolchain
-      - name: Set up Python environment
+        uses: actions/setup-python@v5
-        run: |
+        with:
-          curl https://bootstrap.pypa.io/get-pip.py -o get-pip.py
+          python-version: "3.13"
-          python3 get-pip.py
+          cache: pip
-          python3 -m pip install virtualenv
+      - name: Set up the Python environment
-          python3 -m virtualenv venv
+        run: pip install -r requirements.txt
-          source venv/bin/activate
+      - name: Type-check the code
-          pip install -r requirements.txt
+        run: mypy *.py
-      - name: Type-check
-        run: |
-          source venv/bin/activate
-          mypy *.py