Add 7.8.2 version constant.

.ci/bwcVersions

@@ -21,6 +21,7 @@ BWC_VERSION:
   - "7.7.1"
   - "7.8.0"
   - "7.8.1"
+  - "7.8.2"
   - "7.9.0"
   - "7.10.0"
   - "8.0.0"

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

@@ -79,6 +79,7 @@ public class Version implements Comparable<Version>, ToXContentFragment {
     public static final Version V_7_7_1 = new Version(7070199, org.apache.lucene.util.Version.LUCENE_8_5_1);
     public static final Version V_7_8_0 = new Version(7080099, org.apache.lucene.util.Version.LUCENE_8_5_1);
     public static final Version V_7_8_1 = new Version(7080199, org.apache.lucene.util.Version.LUCENE_8_5_1);
+    public static final Version V_7_8_2 = new Version(7080299, org.apache.lucene.util.Version.LUCENE_8_5_1);
     public static final Version V_7_9_0 = new Version(7090099, org.apache.lucene.util.Version.LUCENE_8_6_0);
     public static final Version V_7_10_0 = new Version(7100099, org.apache.lucene.util.Version.LUCENE_8_6_0);
     public static final Version V_8_0_0 = new Version(8000099, org.apache.lucene.util.Version.LUCENE_8_6_0);