remove 8.18.2 refs

Author: leemthompo

docs/reference/release-notes.asciidoc

@@ -6,7 +6,6 @@
 
 This section summarizes the changes in each release.
 
-* <<release-notes-8.18.2>>
 * <<release-notes-8.18.1>>
 * <<release-notes-8.18.0>>
 * <<release-notes-8.17.6>>
@@ -92,7 +91,6 @@ This section summarizes the changes in each release.
 
 --
 
-include::release-notes/8.18.2.asciidoc[]
 include::release-notes/8.18.1.asciidoc[]
 include::release-notes/8.18.0.asciidoc[]
 include::release-notes/8.17.6.asciidoc[]