Update CHANGES.txt for 3.20.0 release (#9581)

CHANGES.txt

@@ -1,6 +1,11 @@
-Unreleased Changes (C++/Java/Python/PHP/Objective-C/C#/Ruby/JavaScript)
+2022-03-04 version 3.20.0 (C++/Java/Python/PHP/Objective-C/C#/Ruby/JavaScript)
 
   Ruby
+  * Dropped Ruby 2.3 and 2.4 support for CI and releases. (#9311)
+  * Message.decode/encode: Add max_recursion_depth option (#9218)
+  * Rename max_recursion_depth to recursion_limit (#9486)
+  * Fix conversion of singleton classes in Ruby (#9342)
+  * Suppress warning for intentional circular require (#9556)
   * JSON will now output shorter strings for double and float fields when possible
     without losing precision.
   * Encoding and decoding of binary format will now work properly on big-endian
@@ -10,6 +15,8 @@ Unreleased Changes (C++/Java/Python/PHP/Objective-C/C#/Ruby/JavaScript)
     putting such values in unknown fields.
 
   Java
+  * Revert "Standardize on Array copyOf" (#9400)
+  * Resolve more java field accessor name conflicts (#8198)
   * Don't support map fields in DynamicMessage.Builder.{getFieldBuilder,getRepeatedFieldBuilder}
   * Fix parseFrom to only throw InvalidProtocolBufferException
   * InvalidProtocolBufferException now allows arbitrary wrapped Exception types.
@@ -17,30 +24,33 @@ Unreleased Changes (C++/Java/Python/PHP/Objective-C/C#/Ruby/JavaScript)
   * Flush CodedOutputStream also flushes underlying OutputStream
   * When oneof case is the same and the field type is Message, merge the
     subfield. (previously it was replaced.)’
-  * add @CheckReturnValue to some protobuf types
+  * Add @CheckReturnValue to some protobuf types
   * Report original exceptions when parsing JSON
   * Add more info to @deprecated javadoc for set/get/has methods
   * Fix initialization bug in doc comment line numbers
   * Fix comments for message set wire format.
 
   Kotlin
+  * Add test scope to kotlin-test for protobuf-kotlin-lite (#9518)
   * Add orNull extensions for optional message fields.
   * Add orNull extensions to all proto3 message fields.
 
   Python
+  * Dropped support for Python < 3.7 (#9480)
+  * Protoc is now able to generate python stubs (.pyi) with --pyi_out
+  * Pin multibuild scripts to get manylinux1 wheels back (#9216)
   * Fix type annotations of some Duration and Timestamp methods.
   * Repeated field containers are now generic in field types and could be used
     in type annotations.
   * Protobuf python generated codes are simplified. Descriptors and message
     classes' definitions are now dynamic created in internal/builder.py.
     Insertion Points for messages classes are discarded.
-  * protoc is now able to generate python stub (.pyi) by --gen_pyi
   * has_presence is added for FieldDescriptor in python
   * Loosen indexing type requirements to allow valid __index__() implementations
     rather than only PyLongObjects.
   * Fix the deepcopy bug caused by not copying message_listener.
   * Added python JSON parse recursion limit (default 100)
-  * path info is added for python JSON parse errors
+  * Path info is added for python JSON parse errors
   * Pure python repeated scalar fields will not able to pickle. Convert to list
     first.
   * Timestamp.ToDatetime() now accepts an optional tzinfo parameter. If
@@ -82,18 +92,37 @@ Unreleased Changes (C++/Java/Python/PHP/Objective-C/C#/Ruby/JavaScript)
   * Implement on demand register ArenaDtor for InlinedStringField
 
   C++
-  * manually *struct Cord fields to work better with arenas.
-  * manually destruct map fields.
+  * Enable testing via CTest (#8737)
+  * Add option to use external GTest in CMake (#8736)
+  * CMake: Set correct sonames for libprotobuf-lite.so and libprotoc.so (#8635) (#9529)
+  * Add cmake option `protobuf_INSTALL` to not install files (#7123)
+  * CMake: Allow custom plugin options e.g. to generate mocks (#9105)
+  * CMake: Use linker version scripts (#9545)
+  * Manually *struct Cord fields to work better with arenas.
+  * Manually destruct map fields.
   * Generate narrower code
   * Fix https://github.com/protocolbuffers/protobuf/issues/9378 by removing
     shadowed _cached_size_ field
   * Remove GetPointer() and explicit nullptr defaults.
-  * add proto_h flag for speeding up large builds
+  * Add proto_h flag for speeding up large builds
   * Add missing overload for reference wrapped fields.
   * Add MergedDescriptorDatabase::FindAllFileNames()
   * RepeatedField now defines an iterator type instead of using a pointer.
   * Remove obsolete macros GOOGLE_PROTOBUF_HAS_ONEOF and GOOGLE_PROTOBUF_HAS_ARENAS.
 
+  PHP
+  * Fix: add missing reserved classnames (#9458)
+
+  C#
+  * Fix trim warnings (#9182)
+  * Fixes NullReferenceException when accessing FieldDescriptor.IsPacked (#9430)
+  * Add ToProto() method to all descriptor classes (#9426)
+  * Add an option to preserve proto names in JsonFormatter (#6307)
+
+  Objective-C
+  * Add prefix_to_proto_package_mappings_path option. (#9498)
+  * Rename `proto_package_to_prefix_mappings_path` to `package_to_prefix_mappings_path`. (#9552)
+  * Add a generation option to control use of forward declarations in headers. (#9568)
 
 2022-01-28 version 3.19.4 (C++/Java/Python/PHP/Objective-C/C#/Ruby/JavaScript)