Update actions workflow to run in self hosted runners with spread ins…

…talled

As spread has moved to Canonical org, it is required to add a tag to the
runners with spread pre-installed and confugured to run in google.

In all the projects we are using the tag spread-enabled to differentiate
the runners with spread and the org runners without it.

.github/workflows/test.yaml

@@ -11,7 +11,7 @@ on:
 
 jobs:
   run-tests:
-    runs-on: self-hosted
+    runs-on: '["self-hosted", "spread-enabled"]'
     steps:
       - uses: actions/checkout@v2