Stop testing against Hibernate ORM 6.3

We know it won't work because RootGraph#appliesTo was removed in OR< 6.3.

Hibernate Search 6.2, on the other hand, will work fine with ORM 6.3.
See https://hibernate.atlassian.net/browse/HSEARCH-4890

ci/dependency-update/Jenkinsfile

@@ -27,11 +27,6 @@ Map settings() {
 					updateProperties: ['version.org.hibernate.orm'],
 					onlyRunTestDependingOn: ['hibernate-search-mapper-orm-orm6']
 			]
-		case 'orm6.3':
-			return [
-					updateProperties: ['version.org.hibernate.orm'],
-					onlyRunTestDependingOn: ['hibernate-search-mapper-orm-orm6']
-			]
 		case 'orm6.2':
 			return [
 					updateProperties: ['version.org.hibernate.orm'],
@@ -134,7 +129,7 @@ pipeline {
 					axis {
 						name 'DEPENDENCY_UPDATE_NAME'
 						// NOTE: Remember to update the settings() method above when changing this.
-						values 'orm5.6', 'orm6.0', 'orm6.1', 'orm6.2', 'orm6.3'
+						values 'orm5.6', 'orm6.0', 'orm6.1', 'orm6.2'
 					}
 				}
 				stages {