introduce 6.8.3 as a version (#44706)

Author: jakelandis

server/src/main/java/org/elasticsearch/Version.java

@@ -97,6 +97,7 @@ public class Version implements Comparable<Version>, ToXContentFragment {
     public static final Version V_6_8_0 = new Version(6080099, org.apache.lucene.util.Version.LUCENE_7_7_0);
     public static final Version V_6_8_1 = new Version(6080199, org.apache.lucene.util.Version.LUCENE_7_7_0);
     public static final Version V_6_8_2 = new Version(6080299, org.apache.lucene.util.Version.LUCENE_7_7_0);
+    public static final Version V_6_8_3 = new Version(6080399, org.apache.lucene.util.Version.LUCENE_7_7_0);
     public static final Version V_7_0_0 = new Version(7000099, org.apache.lucene.util.Version.LUCENE_8_0_0);
     public static final Version V_7_0_1 = new Version(7000199, org.apache.lucene.util.Version.LUCENE_8_0_0);
     public static final Version V_7_1_0 = new Version(7010099, org.apache.lucene.util.Version.LUCENE_8_0_0);