learning rate scheduler does not appear to step                                                       
🐛 Bug

when using learning rate scheduler from PyTorch, it appears that it does not step
Please reproduce using the BoringModel and post here
Yes I used the notebook above and the only thing I did is to add callback to the trainer. See code below
To Reproduce

from pytorch_lightning.callbacks import LearningRateMonitor
def test_x(tmpdir):
    # init model
    model = BoringModel()

    lr_monitor = LearningRateMonitor(logging_interval='step')

    # Initialize a trainer
    trainer = pl.Trainer(
        max_epochs=1, 
        progress_bar_refresh_rate=20,
        callbacks=[lr_monitor]
    )

    # Train the model ⚡
    trainer.fit(model, train, val)

    trainer.test(test_dataloaders=test)

After the code run, open the log using tensorboard
%load_ext tensorboard
%tensorboard --logdir lightning_logs --reload_interval 1

and look for the lr-SGD curve and I find it flat instead of gradually decrease 10% (gamma=0.1 by default) every 10 steps.

Here is the link for my notebook
https://colab.research.google.com/drive/10l3Kz-9rOP7lu5qrLurJj-2m-lio8SmE?usp=sharing
Expected behavior
learning rate schedule should step

Environment
Note: Bugs with code are solved faster ! Colab Notebook should be made public !


IDE: Please, use our python bug_report_model.py template.


Colab Notebook: Please copy and paste the output from our environment collection script (or fill out the checklist below manually).


You can get the script and run it with:
wget https://raw.githubusercontent.com/PyTorchLightning/pytorch-lightning/master/tests/collect_env_details.py
# For security purposes, please check the contents of collect_env_details.py before running it.
python collect_env_details.py


CUDA:

GPU:

Tesla V100-SXM2-16GB


available:         True
version:           10.1


Packages:

numpy:             1.18.5
pyTorch_debug:     True
pyTorch_version:   1.7.0+cu101
pytorch-lightning: 1.0.5
tqdm:              4.41.1


System:

OS:                Linux
architecture:

64bit



processor:         x86_64
python:            3.6.9
version:           #1 SMP Thu Jul 23 08:00:38 PDT 2020



Additional context