update CHANGELOG

CHANGELOG.md

@@ -4,18 +4,25 @@ Nokogiri follows [Semantic Versioning](https://semver.org/), please see the [REA
 
 ---
 
+## 1.12.3 / unreleased
+
+### Fixed
+
+* [CRuby] Fix compilation of libgumbo on older systems with versions of GCC that give errors on C99-isms. Affected systems include RHEL6, RHEL7, and SLES12. [[#2302](https://github.com/sparklemotion/nokogiri/issues/2302)]
+
+
 ## 1.12.2 / 2021-08-04
 
 ### Fixed
 
-* Ensure that C extension files in non-native gem installations are loaded using `require` and rely on `$LOAD_PATH` instead of using `require_relative`. This issue only exists when deleting shared libraries that exist outside the extensions directory, something users occasionally do to conserve disk space. [[#2300](https://github.com/sparklemotion/nokogiri/issues/2300)]
+* [CRuby] Ensure that C extension files in non-native gem installations are loaded using `require` and rely on `$LOAD_PATH` instead of using `require_relative`. This issue only exists when deleting shared libraries that exist outside the extensions directory, something users occasionally do to conserve disk space. [[#2300](https://github.com/sparklemotion/nokogiri/issues/2300)]
 
 
 ## 1.12.1 / 2021-08-03
 
 ### Fixed
 
-* Fix compilation of libgumbo on BSD systems by avoiding GNU-isms. [[#2298](https://github.com/sparklemotion/nokogiri/issues/2298)]
+* [CRuby] Fix compilation of libgumbo on BSD systems by avoiding GNU-isms. [[#2298](https://github.com/sparklemotion/nokogiri/issues/2298)]
 
 
 ## 1.12.0 / 2021-08-02