fix: use --without-pip venv + get-pip.py (ensurepip broken on RISE runner)

Author: gounthar

.github/workflows/build-riscv64.yml

@@ -28,10 +28,11 @@ jobs:
 
       - name: Set up Python
         run: |
-          sudo apt-get install -y python3-venv python3-pip
-          python3 -m venv /tmp/build-venv
+          sudo apt-get install -y python3-venv python3-pip python3-dev
+          python3 -m venv --without-pip /tmp/build-venv
           . /tmp/build-venv/bin/activate
-          pip install --upgrade pip setuptools wheel
+          curl -sS https://bootstrap.pypa.io/get-pip.py | python3
+          pip install --upgrade setuptools wheel
 
       - name: Build wheel
         run: |