8.14.2: add missing changelog entry (#13555)

Intially only merged on 8.14 branch, should have been merged on
main and backported.

Also add a missing changelog entry

changelogs/8.14.asciidoc

@@ -1,9 +1,21 @@
 [[apm-release-notes-8.14]]
 == APM version 8.14
 
+* <<apm-release-notes-8.14.2>>
 * <<apm-release-notes-8.14.1>>
 * <<apm-release-notes-8.14.0>>
 
+[float]
+[[apm-release-notes-8.14.2]]
+=== APM version 8.14.2
+
+https://github.com/elastic/apm-server/compare/v8.14.1\...v8.14.2[View commits]
+
+No significant changes.
+
+=== Added
+- Optimize memory usage and disk read IO for Tail Based Sampling {pull}13464[13464]
+
 [float]
 [[apm-release-notes-8.14.1]]
 === APM version 8.14.1