Install pip in Python virtual environment setup

Added a step to download and install pip in the CI workflow.

.github/workflows/build.yml

@@ -482,6 +482,8 @@ jobs:
       - name: Create and use Python venv
         run: |
           cd "$GITHUB_WORKSPACE"
+          curl -o get-pip.py https://bootstrap.pypa.io/get-pip.py
+          "$PYTHON" get-pip.py
           "$PYTHON" -m venv venv
           if [[ "$RUNNER_OS" == "Windows" ]]; then
             # hack till pyscard has a wheel for win arm64