fixing integration/test_application

Author: cderici

tests/integration/test_application.py

@@ -170,7 +170,7 @@ async def test_upgrade_local_charm(event_loop):
     async with base.CleanModel() as model:
         tests_dir = Path(__file__).absolute().parent
         charm_path = tests_dir / 'upgrade-charm'
-        app = await model.deploy('ubuntu', series='focal')
+        app = await model.deploy('cs:ubuntu', series='focal')
         await model.wait_for_idle(status="active")
         assert app.data['charm-url'].startswith('cs:ubuntu')
         await app.upgrade_charm(path=charm_path)