feat(gke): Publish package version for GKE (#786)

Running Baseplate applications in GKE requires some changes to the way
Baseplate works, for example we need to remove reliance on POSIX queues.
After this change we will start publishing a baseplate package version
v2.5-unsupported-gcp. This branch will contain any changed needed for
Baseplate application to work in GKE.

.github/workflows/python-package.yaml

@@ -2,9 +2,9 @@ name: Lint and Test
 
 on:
   push:
-    branches: [ develop ]
+    branches: [ develop, v2.5, v2.5-unsupported-gcp ]
   pull_request:
-    branches: [ develop ]
+    branches: [ develop, v2.5, v2.5-unsupported-gcp ]
 
 jobs:
   lint-and-test: