Change version to 2.12.0 for cluster state stats (opensearch-project#…

…10915)

Signed-off-by: Aman Khare <amkhar@amazon.com>
Co-authored-by: Aman Khare <amkhar@amazon.com>
Signed-off-by: Shivansh Arora <hishiv@amazon.com>

server/src/main/java/org/opensearch/discovery/DiscoveryStats.java

@@ -64,7 +64,7 @@ public DiscoveryStats(PendingClusterStateStats queueStats, PublishClusterStateSt
     public DiscoveryStats(StreamInput in) throws IOException {
         queueStats = in.readOptionalWriteable(PendingClusterStateStats::new);
         publishStats = in.readOptionalWriteable(PublishClusterStateStats::new);
-        if (in.getVersion().onOrAfter(Version.V_3_0_0)) {
+        if (in.getVersion().onOrAfter(Version.V_2_12_0)) {
             clusterStateStats = in.readOptionalWriteable(ClusterStateStats::new);
         } else {
             clusterStateStats = null;
@@ -75,7 +75,7 @@ public DiscoveryStats(StreamInput in) throws IOException {
     public void writeTo(StreamOutput out) throws IOException {
         out.writeOptionalWriteable(queueStats);
         out.writeOptionalWriteable(publishStats);
-        if (out.getVersion().onOrAfter(Version.V_3_0_0)) {
+        if (out.getVersion().onOrAfter(Version.V_2_12_0)) {
             out.writeOptionalWriteable(clusterStateStats);
         }
     }