PL: update changelog post 1.7.5 release (#14570)

Co-authored-by: Jirka Borovec <[email protected]>

Author: krshrimali

src/pytorch_lightning/CHANGELOG.md

@@ -4,7 +4,7 @@ All notable changes to this project will be documented in this file.
 
 The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 
-## [1.8.0] - 2022-MM-DD
+## [unReleased] - 2022-MM-DD
 
 ### Added
 
@@ -158,11 +158,13 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 - Fixed an issue to keep downscaling the batch size in case there hasn't been even a single successful optimal batch size with `mode="power"` ([#14372](https://github.com/Lightning-AI/lightning/pull/14372))
 
 
-- Squeezed tensor values when logging with `LightningModule.log` ([#14489](https://github.com/Lightning-AI/lightning/pull/14489))
+## [1.7.5] - 2022-09-06
 
+### Fixed
 
+- Squeezed tensor values when logging with `LightningModule.log` ([#14489](https://github.com/Lightning-AI/lightning/pull/14489))
 - Fixed `WandbLogger` `save_dir` is not set after creation ([#14326](https://github.com/Lightning-AI/lightning/pull/14326))
-
+- Fixed `Trainer.estimated_stepping_batches` when maximum number of epochs is not set ([#14317](https://github.com/Lightning-AI/lightning/pull/14317))
 
 
 ## [1.7.4] - 2022-08-31