Revert "Bump versions after 8.18.0 release"

This reverts commit bc9cc7b.

Author: brianseeders

.buildkite/pipelines/periodic-packaging.yml

@@ -579,8 +579,8 @@ steps:
         env:
           BWC_VERSION: 8.15.5
 
-      - label: "{{matrix.image}} / 8.16.5 / packaging-tests-upgrade"
-        command: ./.ci/scripts/packaging-test.sh -Dbwc.checkout.align=true destructiveDistroUpgradeTest.v8.16.5
+      - label: "{{matrix.image}} / 8.16.6 / packaging-tests-upgrade"
+        command: ./.ci/scripts/packaging-test.sh -Dbwc.checkout.align=true destructiveDistroUpgradeTest.v8.16.6
         timeout_in_minutes: 300
         matrix:
           setup:
@@ -593,7 +593,7 @@ steps:
           machineType: custom-16-32768
           buildDirectory: /dev/shm/bk
         env:
-          BWC_VERSION: 8.16.5
+          BWC_VERSION: 8.16.6
 
       - label: "{{matrix.image}} / 8.17.6 / packaging-tests-upgrade"
         command: ./.ci/scripts/packaging-test.sh -Dbwc.checkout.align=true destructiveDistroUpgradeTest.v8.17.6

.buildkite/pipelines/periodic.yml

@@ -648,8 +648,8 @@ steps:
             - signal_reason: agent_stop
               limit: 3
 
-      - label: 8.16.5 / bwc
-        command: .ci/scripts/run-gradle.sh -Dbwc.checkout.align=true v8.16.5#bwcTest
+      - label: 8.16.6 / bwc
+        command: .ci/scripts/run-gradle.sh -Dbwc.checkout.align=true v8.16.6#bwcTest
         timeout_in_minutes: 300
         agents:
           provider: gcp
@@ -658,7 +658,7 @@ steps:
           buildDirectory: /dev/shm/bk
           preemptible: true
         env:
-          BWC_VERSION: 8.16.5
+          BWC_VERSION: 8.16.6
         retry:
           automatic:
             - exit_status: "-1"

.ci/bwcVersions

@@ -33,6 +33,6 @@ BWC_VERSION:
   - "8.13.4"
   - "8.14.3"
   - "8.15.5"
-  - "8.16.5"
+  - "8.16.6"
   - "8.17.6"
   - "8.18.1"

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

@@ -198,6 +198,7 @@ public class Version implements VersionId<Version>, ToXContentFragment {
     public static final Version V_8_16_3 = new Version(8_16_03_99);
     public static final Version V_8_16_4 = new Version(8_16_04_99);
     public static final Version V_8_16_5 = new Version(8_16_05_99);
+    public static final Version V_8_16_6 = new Version(8_16_06_99);
     public static final Version V_8_17_0 = new Version(8_17_00_99);
     public static final Version V_8_17_1 = new Version(8_17_01_99);
     public static final Version V_8_17_2 = new Version(8_17_02_99);