Added bwc version 1.3.21 (opensearch-project#16845)

Signed-off-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
Signed-off-by: Andriy Redko <[email protected]>
Co-authored-by: opensearch-ci-bot <[email protected]>

Author: reta

.ci/bwcVersions

@@ -57,6 +57,7 @@ BWC_VERSION:
   - "1.3.18"
   - "1.3.19"
   - "1.3.20"
+  - "1.3.21"
   - "2.0.0"
   - "2.0.1"
   - "2.0.2"

libs/core/src/main/java/org/opensearch/Version.java

@@ -100,6 +100,7 @@ public class Version implements Comparable<Version>, ToXContentFragment {
     public static final Version V_1_3_18 = new Version(1031899, org.apache.lucene.util.Version.LUCENE_8_10_1);
     public static final Version V_1_3_19 = new Version(1031999, org.apache.lucene.util.Version.LUCENE_8_10_1);
     public static final Version V_1_3_20 = new Version(1032099, org.apache.lucene.util.Version.LUCENE_8_10_1);
+    public static final Version V_1_3_21 = new Version(1032199, org.apache.lucene.util.Version.LUCENE_8_10_1);
     public static final Version V_2_0_0 = new Version(2000099, org.apache.lucene.util.Version.LUCENE_9_1_0);
     public static final Version V_2_0_1 = new Version(2000199, org.apache.lucene.util.Version.LUCENE_9_1_0);
     public static final Version V_2_0_2 = new Version(2000299, org.apache.lucene.util.Version.LUCENE_9_1_0);