uninstall system meshtastic

.github/workflows/ci.yml

@@ -16,6 +16,9 @@ jobs:
         uses: actions/setup-python@v1
         with:
           python-version: 3.9
+      - name: Uninstall meshtastic
+        run: |
+          pip3 uninstall meshtastic
       - name: Install dependencies
         run: |
           python -m pip install --upgrade pip