Enable Gerrit builds on stable-3.12

Validate incoming changes on stable-3.12 and build Gerrit and
plugins for the stable-3.12 branch.

Change-Id: Id283ac23f65a0baa94ad049a568920593410c460

Author: lucamilanesio

jenkins/gerrit-bazel-plugin-template.yaml

@@ -285,6 +285,7 @@
       - 'Plugins-{branch}'
     branch:
       - master
+      - stable-3.12
       - stable-3.11
       - stable-3.10
       - stable-3.9

jenkins/gerrit-bazel-template.yaml

@@ -79,6 +79,7 @@
       - 'Gerrit-bazel-{branch}':
           branch:
             - master
+            - stable-3.12
             - stable-3.11
             - stable-3.10
             - stable-3.9

jenkins/gerrit-bazel-verifier-test.sh

@@ -8,11 +8,11 @@ echo "Test with mode=$MODE"
 echo '----------------------------------------------'
 
 case $TARGET_BRANCH$MODE in
-  masterrbe|stable-3.9rbe|stable-3.10rbe|stable-3.11rbe)
+  masterrbe|stable-3.9rbe|stable-3.10rbe|stable-3.11rbe|stable-3.12rbe)
     TEST_TAG_FILTER="-flaky,-elastic,-no_rbe,-lucene"
     BAZEL_OPTS="$BAZEL_OPTS --config=remote_bb --jobs=50 --remote_header=x-buildbuddy-api-key=$BB_API_KEY"
     ;;
-  masternotedb|stable-3.9notedb|stable-3.10notedb|stable-3.11notedb)
+  masternotedb|stable-3.9notedb|stable-3.10notedb|stable-3.11notedb|stable-3.12notedb)
     TEST_TAG_FILTER="-flaky,elastic,no_rbe"
     ;;
   stable-2.*)

vars/gerritPipeline.groovy

@@ -130,7 +130,7 @@ def queryChangedFiles(url) {
 
 def collectBuildModes() {
     Builds.modes = []
-    if (env.GERRIT_BRANCH == "master" || env.GERRIT_BRANCH == "stable-3.9" || env.GERRIT_BRANCH ==~ /stable-3.1[0-1]/) {
+    if (env.GERRIT_BRANCH == "master" || env.GERRIT_BRANCH == "stable-3.9" || env.GERRIT_BRANCH ==~ /stable-3.1[0-2]/) {
         Builds.modes = ["notedb", "rbe"]
     } else {
         throw new Exception("Unsupported branch ${env.GERRIT_BRANCH}")