test: Run Performance A/B-Tests on release branches

Since we no longer need to maintain separate sets of baselines for each
release branch, it becomes feasible to run performance tests on release
branches. These only trigger when PRs are merged.

Signed-off-by: Patrick Roy <[email protected]>

Author: roypat

.github/workflows/trigger_ab_tests.yml

@@ -2,6 +2,7 @@ on:
   push:
     branches:
       - main
+      - firecracker-v*
 
 jobs:
   trigger_ab_test: