Bump version after 7.15.0 release

.ci/bwcVersions

@@ -43,5 +43,6 @@ BWC_VERSION:
   - "7.14.2"
   - "7.14.3"
   - "7.15.0"
+  - "7.15.1"
   - "7.16.0"
   - "8.0.0"

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

@@ -90,6 +90,7 @@ public class Version implements Comparable<Version>, ToXContentFragment {
     public static final Version V_7_14_2 = new Version(7140299, org.apache.lucene.util.Version.LUCENE_8_9_0);
     public static final Version V_7_14_3 = new Version(7140399, org.apache.lucene.util.Version.LUCENE_8_9_0);
     public static final Version V_7_15_0 = new Version(7150099, org.apache.lucene.util.Version.LUCENE_8_9_0);
+    public static final Version V_7_15_1 = new Version(7150199, org.apache.lucene.util.Version.LUCENE_8_9_0);
     public static final Version V_7_16_0 = new Version(7160099, org.apache.lucene.util.Version.LUCENE_8_10_0);
     public static final Version V_8_0_0 = new Version(8000099, org.apache.lucene.util.Version.LUCENE_9_0_0);
     public static final Version CURRENT = V_8_0_0;