fix(layer): standard latest keras layer

[LongxingTan]

Description

This PR ...

Checklist

• Linked issues (if existing)
• Amended changelog.md for large changes (and added myself there as contributor)
• Added/modified tests
• Used pre-commit hooks when committing to ensure that code is compliant with hooks. Install hooks with pre-commit install.
  To run hooks independent of commit, execute pre-commit run --all-files

Thank you for joining. Have fun coding!

[codecov]

Codecov Report

❌ Patch coverage is 70.68063% with 56 lines in your changes missing coverage. Please review.
✅ Project coverage is 83.87%. Comparing base (bad1cfa) to head (0fa09d4).
⚠️ Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
tfts/layers/nbeats_layer.py	40.00%	15 Missing ⚠️
tfts/models/tcn.py	72.50%	11 Missing ⚠️
tfts/layers/attention_layer.py	0.00%	10 Missing ⚠️
tfts/models/seq2seq.py	65.00%	7 Missing ⚠️
tfts/models/wavenet.py	88.37%	5 Missing ⚠️
tfts/layers/util_layer.py	69.23%	4 Missing ⚠️
tfts/models/rnn.py	40.00%	3 Missing ⚠️
tfts/layers/dense_layer.py	75.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master      #74      +/-   ##
==========================================
- Coverage   84.45%   83.87%   -0.58%     
==========================================
  Files          44       44              
  Lines        3698     3795      +97     
==========================================
+ Hits         3123     3183      +60     
- Misses        575      612      +37     

Flag	Coverage Δ
cpu	83.87% <70.68%> (-0.58%)	⬇️
unittest	83.87% <70.68%> (-0.58%)	⬇️

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