[paddle-pipelines] Update mkdocs

[w5688414]

PR types

PR changes

Description

readthedocs编译的时候，requirements.txt找错了，导致编译失败：

PaddleNLP/docs/requirements.txt

Line 3 in e67fd78

urllib3==1.26.2 # fix urllib3 version dependency: https://github.com/psf/requests/issues/6432#issuecomment-1537221990

应该找pipelines目录下的docs/requirements.txt

[paddle-bot]

Thanks for your contribution!

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 55.33%. Comparing base (e67fd78) to head (8e729fb).
Report is 2 commits behind head on develop.

❗ Current head 8e729fb differs from pull request most recent head b8456b1. Consider uploading reports for the commit b8456b1 to get more accurate results

Additional details and impacted files

@@           Coverage Diff            @@
##           develop    #8310   +/-   ##
========================================
  Coverage    55.33%   55.33%           
========================================
  Files          614      614           
  Lines        95341    95341           
========================================
  Hits         52753    52753           
  Misses       42588    42588           

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