Fix k8s upgrade tests for releases, by setting target branch value
to capm3_release_branch value

Change-Id: I9cadd7ed94600bb07b881108c41d3dd19624d27b
diff --git a/jjb/metal3/job_capm3_main_e2e_k8s_upgrade_tests.yml b/jjb/metal3/job_capm3_main_e2e_k8s_upgrade_tests.yml
index c3518fb..21666f1 100644
--- a/jjb/metal3/job_capm3_main_e2e_k8s_upgrade_tests.yml
+++ b/jjb/metal3/job_capm3_main_e2e_k8s_upgrade_tests.yml
@@ -43,7 +43,7 @@
         description: 'Project github repo name'
     - string:
         name: ghprbActualCommit
-        default: 'main'
+        default: '{capm3_release_branch}'
         description: 'CI Repo branch for triggering manual build'
     - string:
         name: ghprbAuthorRepoGitUrl
@@ -51,7 +51,7 @@
         description: 'CI Repo URL for triggering manual build'
     - string:
         name: ghprbTargetBranch
-        default: 'main'
+        default: '{capm3_release_branch}'
         description: 'Target branch of the PR'
     - string:
         name: IMAGE_OS