ci: target release-X.Y.x branches instead of release-X.Y.x-maint (#3995)

We will be updating our release procedure to be more "normal" or "sane".
We will
- create release branches like normal people
- land cherry-picks onto those branches
- run releases off of those branches
- no more "rc" branch pollution either

Given that, this PR cleans things up a bit
- Remove `-maint` suffix from release branch patterns in CI workflows
- Update branch matching to `release-X.Y.x` format

.github/workflows/integration-vector-io-tests.yml

@@ -4,9 +4,17 @@ run-name: Run the integration test suite with various VectorIO providers
 
 on:
   push:
-    branches: [ main ]
+    branches:
+      - main
+      - 'release-[0-9]+.[0-9]+.[0-9]+.[0-9]+'
+      - 'release-[0-9]+.[0-9]+.[0-9]+'
+      - 'release-[0-9]+.[0-9]+'
   pull_request:
-    branches: [ main ]
+    branches:
+      - main
+      - 'release-[0-9]+.[0-9]+.[0-9]+.[0-9]+'
+      - 'release-[0-9]+.[0-9]+.[0-9]+'
+      - 'release-[0-9]+.[0-9]+'
     paths:
       - 'llama_stack/**'
       - '!llama_stack/ui/**'