update changelog

Author: speediedan

CHANGELOG.md

@@ -77,6 +77,9 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 
 ### Changed
 
+- Deprecated `Trainer.{validated,tested,predicted}_ckpt_path` and replaced with read-only property `Trainer.ckpt_path` set when checkpoints loaded via `Trainer.{fit,validate,test,predict}` ([#11696](https://github.com/PyTorchLightning/pytorch-lightning/pull/11696))
+
+
 - Set the `prog_bar` flag to False in `LightningModule.log_grad_norm` ([#11472](https://github.com/PyTorchLightning/pytorch-lightning/pull/11472))