add feature to use extra index URL

.gitea/workflows/python-checks.yml

@@ -21,6 +21,9 @@ on:
       run_security_scan:
         type: boolean
         default: true
+      use_private_index:
+        type: boolean
+        default: false
 
 jobs:
   check:
@@ -35,6 +38,17 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v4
 
+      - name: Configure private package index
+        if: ${{ inputs.use_private_index }}
+        env:
+          PRIVATE_INDEX_URL: ${{ secrets.PIP_EXTRA_INDEX_URL }}
+        run: |
+          if [ -z "$PRIVATE_INDEX_URL" ]; then
+            echo "use_private_index=true but the PIP_EXTRA_INDEX_URL secret is empty or not set"
+            exit 1
+          fi
+          pip config --site set global.extra-index-url "$PRIVATE_INDEX_URL"
+
       - name: Install Tools & Deps
         run: |
           python -m pip install --upgrade pip setuptools wheel