ES-1621: active forward merge automation (#1335)

.ci/dev/forward-merge/JenkinsfileMergeAutomation

@@ -0,0 +1,33 @@
+#! groovy
+@Library('[email protected]') _
+
+/**
+ * Forward merge any changes in current branch to the branch with following version.
+ *
+ * Please note, the branches names are intentionally separated as variables, to minimised conflicts
+ * during automated merges for this file.
+ *
+ * These variables should be updated when a new version is cut
+ */
+
+/**
+ * the branch name of origin branch, it should match the current branch
+ * and it acts as a fail-safe inside {@code forwardMerger} pipeline
+ */
+String originBranch = 'release/os/5.1'
+
+/**
+ * the branch name of target branch, it should be the branch with the next version
+ * after the one in current branch.
+ */
+String targetBranch = 'release/os/5.2'
+
+/**
+ * Forward merge any changes between {@code originBranch} and {@code targetBranch}
+ */
+forwardMerger(
+    targetBranch: targetBranch,
+    originBranch: originBranch,
+    slackChannel: '#c5-forward-merge-bot-notifications'
+)
+