Revert "Use apt to install Python modules for actions"

This reverts commit 53361619b9.

.forgejo/workflows/build.yaml

@@ -42,7 +42,8 @@ jobs:
           cache: pip
       - name: Set up Python environment
         run: |
-          apt-get install python3-pip python3-setuptools python3-wheel python3-venv
+          curl https://bootstrap.pypa.io/get-pip.py -o get-pip.py
+          python3 get-pip.py
           python3 -m venv venv
           source venv/bin/activate
           pip install -r requirements.txt