Ensure we have the latest pip version in CI before installing dependencies (#2650)

.github/workflows/main.yml

@@ -68,6 +68,10 @@ jobs:
         shell: bash
         run: poetry run pip --version >/dev/null 2>&1 || rm -rf .venv
 
+      - name: Upgrade pip
+        shell: bash
+        run: poetry run python -m pip install pip -U
+
       - name: Install dependencies
         shell: bash
         run: poetry install