version bump 6.8.0 -> 6.8.1 (#42240)

This commit has 2 changes:

* version bump 6.8.0 -> 6.8.1
* Ensure CI compatibility now that we aren't building any BWC versions
Co-authored-by: Mark Vieira <[email protected]>

Author: jakelandis

buildSrc/version.properties

@@ -1,4 +1,4 @@
-elasticsearch     = 6.8.0
+elasticsearch     = 6.8.1
 lucene            = 7.7.0
 
 # optional dependencies

distribution/bwc/build.gradle

@@ -33,6 +33,8 @@ import static org.elasticsearch.gradle.BuildPlugin.getJavaHome
  *  unreleased versions are when Gradle projects are set up, so we use "build-unreleased-version-*" as placeholders
  *  and configure them to build various versions here.
  */
+task buildBwc
+
 bwcVersions.forPreviousUnreleased { VersionCollection.UnreleasedVersionInfo unreleasedVersion -> project("${project.path}:${unreleasedVersion.gradleProjectName}") {
     Version bwcVersion = unreleasedVersion.version
     String bwcBranch = unreleasedVersion.branch
@@ -192,7 +194,7 @@ bwcVersions.forPreviousUnreleased { VersionCollection.UnreleasedVersionInfo unre
         }
     }
 
-    createRunBwcGradleTask("buildBwcVersion") {
+    buildBwc.dependsOn createRunBwcGradleTask("buildBwcVersion") {
         for (String dir : projectDirs) {
             args ":${dir.replace('/', ':')}:assemble"
         }

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

@@ -214,12 +214,12 @@ public class Version implements Comparable<Version>, ToXContentFragment {
     public static final Version V_6_7_1 = new Version(V_6_7_1_ID, org.apache.lucene.util.Version.LUCENE_7_7_0);
     public static final int V_6_7_2_ID = 6070299;
     public static final Version V_6_7_2 = new Version(V_6_7_2_ID, org.apache.lucene.util.Version.LUCENE_7_7_0);
-    public static final int V_6_7_3_ID = 6070399;
-    public static final Version V_6_7_3 = new Version(V_6_7_3_ID, org.apache.lucene.util.Version.LUCENE_7_7_0);
     public static final int V_6_8_0_ID = 6080099;
     public static final Version V_6_8_0 = new Version(V_6_8_0_ID, org.apache.lucene.util.Version.LUCENE_7_7_0);
+    public static final int V_6_8_1_ID = 6080199;
+    public static final Version V_6_8_1 = new Version(V_6_8_1_ID, org.apache.lucene.util.Version.LUCENE_7_7_0);
 
-    public static final Version CURRENT = V_6_8_0;
+    public static final Version CURRENT = V_6_8_1;
 
     static {
         assert CURRENT.luceneVersion.equals(org.apache.lucene.util.Version.LATEST) : "Version must be upgraded to ["
@@ -232,10 +232,10 @@ public static Version readVersion(StreamInput in) throws IOException {
 
     public static Version fromId(int id) {
         switch (id) {
+            case V_6_8_1_ID:
+                return V_6_8_1;
             case V_6_8_0_ID:
                 return V_6_8_0;
-            case V_6_7_3_ID:
-                return V_6_7_3;
             case V_6_7_2_ID:
                 return V_6_7_2;
             case V_6_7_1_ID: