Update CHANGES

Author: byroot

CHANGES.md

@@ -1,5 +1,9 @@
 # Changes
 
+* Workaround a bug in 3.4.8 and older https://github.com/rubygems/rubygems/pull/6490.
+* Workaround different versions of `json` and `json_pure` being loaded (not officially supported).
+* Make `json_pure` Ractor compatible. 
+
 ### 2024-10-24 (2.7.3)
 
 * Numerous performance optimizations in `JSON.generate` and `JSON.dump` (up to 2 times faster).