Fix warnings in lamb optimizer

[jettify]

No description provided.

[codecov-commenter]

Codecov Report

Merging #163 into master will increase coverage by 0.47%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #163      +/-   ##
==========================================
+ Coverage   86.36%   86.83%   +0.47%     
==========================================
  Files          19       19              
  Lines        1056     1056              
  Branches      247      247              
==========================================
+ Hits          912      917       +5     
+ Misses         80       76       -4     
+ Partials       64       63       -1     

Impacted Files	Coverage Δ
torch_optimizer/lamb.py	83.33% <100.00%> (ø)
torch_optimizer/sgdp.py	84.21% <0.00%> (+6.57%)	⬆️

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