Bump 8.x version to 8.18.0 (#117234)

Author: breskeby

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

@@ -190,6 +190,7 @@ public class Version implements VersionId<Version>, ToXContentFragment {
     public static final Version V_8_16_0 = new Version(8_16_00_99);
     public static final Version V_8_16_1 = new Version(8_16_01_99);
     public static final Version V_8_17_0 = new Version(8_17_00_99);
+    public static final Version V_8_18_0 = new Version(8_18_00_99);
     public static final Version V_9_0_0 = new Version(9_00_00_99);
     public static final Version CURRENT = V_9_0_0;