Updating changelog

CHANGES.txt

@@ -1,3 +1,14 @@
+2022-11-28 version 21.10-rc0 (C++/Java/Python/PHP/Objective-C/C#/Ruby)
+
+  Java
+  * Use bit-field int values in buildPartial to skip work on unset groups of fields. (#10960)
+  * Mark nested builder as clean after clear is called (#10984)
+  UPB
+  * Fix UPB_LIKELY() for 32-bit Windows builds; update protobuf_deps to point to the current upb 21.x (#11028)
+  Other
+  * Add public modifiers to kotlin code (#11068)
+
+
 2022-10-26 version 21.9 (C++/Java/Python/PHP/Objective-C/C#/Ruby)
 
   C++