Fix bug in SchedulerCallback and write all LRs to metrics

[and-kul]

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• Was this discussed/approved via a Github issue? (no need for typos and docs improvements)
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• Did you check the code style? catalyst-make-codestyle && catalyst-check-codestyle (pip install -U catalyst-codestyle).
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Description

1. Fix bug in SchedulerCallback, described in Warning in torch.lr_scheduler #989
2. If you have many param_groups in optimizer then log LRs and momentums for each of them

Related Issue

#989

Type of Change

• Examples / docs / tutorials / contributors update
• Bug fix (non-breaking change which fixes an issue)
• Improvement (non-breaking change which improves an existing feature)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

PR review

Anyone in the community is free to review the PR once the tests have passed.
If we didn't discuss your PR in Github issues there's a high chance it will not be merged.

[pep8speaks]

Hello @and-kul! Thanks for updating this PR. We checked the lines you've touched for PEP 8 issues, and found:

There are currently no PEP 8 issues detected in this Pull Request. Cheers! 🍻

Comment last updated at 2020-12-04 14:55:55 UTC

[Scitator]

could you please check fix the codestyle?
catalyst-make-codestyle && catalyst-check-codestyle (pip install -U catalyst-codestyle).

it would be also cool, if you could drop a minimal example in colab with "how now it working" example :)

[and-kul]

Codestyle is fixed