[CCR] set minimum version to 6.5.0

x-pack/plugin/ccr/src/main/java/org/elasticsearch/xpack/ccr/action/ShardFollowTask.java

@@ -280,6 +280,6 @@ public class ShardFollowTask implements XPackPlugin.XPackPersistentTaskParams {
 
     @Override
     public Version getMinimalSupportedVersion() {
-        return Version.V_6_4_0;
+        return Version.V_6_5_0;
     }
 }