Updated changelog.

CHANGES.txt

@@ -1,15 +1,15 @@
 Unreleased Changes (C++/Java/Python/PHP/Objective-C/C#/Ruby/JavaScript)
-  Protocol Compiler
+  C++
+  * Introduce FieldAccessListener.
   * Stop emitting boilerplate {Copy/Merge}From in each ProtoBuf class
-  * split the accessor annotations according to their operation
-  * introduce proto message injector
-  * let proto message injector decide whether to calculate address info based on field descriptor and access type.
-  * Disable LITE_RUNTIME injector annotations
-  * move callback and @protoc_insertion_point after internal set of enum fields
-  * Improve ExtractFieldInfo codegen for string fields with oneof or default value
-  * Rename MessageInjector to FieldAccessListener
-  * Change the API of FieldAccessListener to support callbacks for info extraction
-  * make field_access_injector private
+  * Fixed some uninitialized variable warnings in generated_message_reflection.cc.
+
+  Kotlin:
+  * Add extension functions related to ByteString to c.g.protobuf.kotlin.
+
+  Java
+  * Fixed parser to check that we are at a proper limit when a sub-message has
+    finished parsing.
 
 2021-05-07 version 3.17.1 (C++/Java/Python/PHP/Objective-C/C#/Ruby/JavaScript)
   PHP