Give users more control on paths used by ModelCheckpoint callback
When initializing a ModelCheckpoint callback like this:
model_checkpoint = ModelCheckpoint(monitor="val_loss", filename="{epoch}-{val_loss:.3f}")
we get checkpoint files with names that look like this:
epoch=1-val_loss=0.436.ckpt

This looks really nice but the use of this name=value pattern is not necessarily what the end user would want.
In particular, tools like hydra will need the end user to escape the = sign:
$ python train.py trainer.resume_from_checkpoint="epoch\=1-val_loss\=0.436.ckpt"
which is not very practical.
Here comes my question: would it be possible to allow for more flexibility on the naming scheme of model checkpoints in ModelCheckpoint callback?
The culprit is this line:

  
    
      pytorch-lightning/pytorch_lightning/callbacks/model_checkpoint.py
    
    
         Line 377
      in
      c208ac6
    
  
  
    

        
          
           filename = filename.replace(group, name + "={" + name)