Update CHANGELOG.md

CHANGELOG.md

@@ -4,18 +4,13 @@ All notable changes to this project will be documented in this file.
 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).
 
-## [Unreleased] - 2021-MM-DD
+## [unReleased] - 2021-MM-DD
 
 ### Added
 
 - Added Advantage Actor-Critic (A2C) Model [#598](https://github.com/PyTorchLightning/lightning-bolts/pull/598))
 
 
-## [unReleased] - 2021-MM-DD
-
-### Added
-
-
 ### Changed
 
 - Changed the default values `pin_memory=False`, `shuffle=False` and `num_workers=16` to `pin_memory=True`, `shuffle=True` and `num_workers=0` of datamodules ([#701](https://github.com/PyTorchLightning/lightning-bolts/pull/701))