add changelog

Author: awaelchli

CHANGELOG.md

@@ -108,6 +108,10 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
     [#8627](https://github.com/PyTorchLightning/pytorch-lightning/pull/8627))
 
 
+- Fixed recursive call for `apply_to_collection(include_none=False)` ([#8719](https://github.com/PyTorchLightning/pytorch-lightning/pull/8719))
+
+
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 ## [1.4.0] - 2021-07-27
 
 ### Added