feat: new CRNN ckpts

[charlesmindee]

This PR updates CRNN TF ckpts due to recents major trainings. Updated documentation as well (~ 1% gain for each dataset)

[codecov]

Codecov Report

Merging #395 (39074ba) into main (d5afb3e) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##             main     #395   +/-   ##
=======================================
  Coverage   95.87%   95.87%           
=======================================
  Files          91       91           
  Lines        3760     3761    +1     
=======================================
+ Hits         3605     3606    +1     
  Misses        155      155           

Flag	Coverage Δ
unittests	95.87% <100.00%> (+<0.01%)	⬆️

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Impacted Files	Coverage Δ
doctr/models/recognition/crnn/tensorflow.py	100.00% <100.00%> (ø)

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[fg-mindee]

Sweet new checkpoint 👌