Prepare changelog for 0.28.0 (#870)

* Prepare changelog for 0.28.0

* Update CHANGELOG.md

* Update release date

Author: testforstephen

CHANGELOG.md

@@ -4,6 +4,18 @@ All notable changes to the "vscode-java-debugger" extension will be documented i
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## 0.28.0 - 2020-08-27
+### Added
+- Add run/debug buttons to editor title bar for single file debugging. [#834](https://github.com/microsoft/vscode-java-debug/issues/834).
+- Add user settings `java.debug.settings.jdwp.limitOfVariablesPerJdwpRequest` and `java.debug.settings.jdwp.requestTimeout` to control JDWP request. [#862](https://github.com/microsoft/vscode-java-debug/pull/862),[#863](https://github.com/microsoft/vscode-java-debug/pull/863).
+
+### Changed
+- Reduce the frequency of JDWP requests to improve performance when expanding VARIABLES view. [#347](https://github.com/microsoft/java-debug/pull/347).
+- Migrate the legacy log to the telemetry wrapper. [#866](https://github.com/microsoft/vscode-java-debug/pull/866).
+
+### Fixed
+- Fix Hot Code Replace error "Cannot find any changed classes for hot replace!". [#855](https://github.com/microsoft/vscode-java-debug/issues/855).
+
 ## 0.27.1 - 2020-07-21
 ### Fixed
 - Hot Code Replace always reports "Cannot find any changed classes for hot replace!". [#850](https://github.com/microsoft/vscode-java-debug/issues/850).