ES-1978: set up 5.3 release branch

.ci/JenkinsfileMergeAutomation

@@ -1,5 +1,5 @@
 #! groovy
-@Library('corda-shared-build-pipeline-steps@5.2') _
+@Library('corda-shared-build-pipeline-steps@5.3') _
 
 /**
  * Forward merge any changes in current branch to the branch with following version.
@@ -14,13 +14,13 @@
  * 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/5.2'
+String originBranch = 'release/5.3'
 
 /**
  * the branch name of target branch, it should be the branch with the next version
  * after the one in current branch.
  */
-String targetBranch = 'release/5.3'
+String targetBranch = 'release/5.4'
 
 /**
  * Forward merge any changes between {@code originBranch} and {@code targetBranch}

.github/CODEOWNERS

@@ -1,2 +1,7 @@
-# Code freeze reviewers
-* @driessamyn @jasonbyrner3 @ronanbrowne @rick-r3 @simon-johnson-r3 @blsemo @Omar-awad @aditisdesai @vinir3 @vkolomeyko @thiagoviana @Sakpal @dickon
+* @corda/rest
+# Build scripts should be audited by BLT
+*.gradle           @corda/blt
+gradle.properties  @corda/corda5-team-leads
+Jenkinsfile        @corda/blt
+.ci/*              @corda/blt
+gradle/*           @corda/blt

gradle.properties

@@ -1,7 +1,7 @@
 kotlin.stdlib.default.dependency=false
 
 # The version of cli-host we will publish
-cliHostVersion=5.2.0
+cliHostVersion=5.3.0
 
 # PF4J
 pf4jVersion=3.10.0