Update CHANGELOG.md

Author: Ravi Chande

CHANGELOG.md

@@ -9,7 +9,7 @@
 * There currently is no completion support for package references in csproj files. ([#1156](https://github.com/OmniSharp/omnisharp-vscode/issues/1156))
   * As an alternative, consider installing the [MSBuild Project Tools](https://marketplace.visualstudio.com/items?itemName=tintoy.msbuild-project-tools) extension by @tintoy.
 
-## 1.21.3 (Not yet released)
+## 1.21.3 (September 18, 2019)
 * Added support for `CheckForOverflowUnderflow ` in csproj files
 * Improved support for .NET Core 3