Introduce version 7.6

Author: jimczi

.ci/bwcVersions

@@ -11,4 +11,5 @@ BWC_VERSION:
   - "7.4.0"
   - "7.4.1"
   - "7.5.0"
+  - "7.6.0"
   - "8.0.0"

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

@@ -69,6 +69,7 @@ public class Version implements Comparable<Version>, ToXContentFragment {
     public static final Version V_7_4_0 = new Version(7040099, org.apache.lucene.util.Version.LUCENE_8_2_0);
     public static final Version V_7_4_1 = new Version(7040199, org.apache.lucene.util.Version.LUCENE_8_2_0);
     public static final Version V_7_5_0 = new Version(7050099, org.apache.lucene.util.Version.LUCENE_8_2_0);
+    public static final Version V_7_6_0 = new Version(7060099, org.apache.lucene.util.Version.LUCENE_8_2_0);
     public static final Version V_8_0_0 = new Version(8000099, org.apache.lucene.util.Version.LUCENE_8_3_0);
     public static final Version CURRENT = V_8_0_0;