docs: Update changelog for 3.1 release

[cloudxxx8]

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PR Checklist

Please check if your PR fulfills the following requirements:

• [x] I am not introducing a breaking change (if you are, flag in conventional commit message with BREAKING CHANGE: describing the break)
• [x] I am not introducing a new dependency (add notes below if you are)
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[codecov-commenter]

Codecov Report

Merging #366 (c43c269) into main (63560b1) will not change coverage. The diff coverage is n/a.

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@@           Coverage Diff           @@
##             main     #366   +/-   ##
=======================================
  Coverage   32.86%   32.86%           
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  Files           2        2           
  Lines         353      353           
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  Hits          116      116           
  Misses        224      224           
  Partials       13       13