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)
• [ ] I have added unit tests for the new feature or bug fix (if not, why?)
• [ ] I have fully tested (add details below) this the new feature or bug fix (if not, why?)
• [ ] I have opened a PR for the related docs change (if not, why?)

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[codecov-commenter]

Codecov Report

Merging #271 (c6683c0) into main (fbcb6d3) will decrease coverage by 0.04%. The diff coverage is n/a.

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@@            Coverage Diff             @@
##             main     #271      +/-   ##
==========================================
- Coverage   41.27%   41.24%   -0.04%     
==========================================
  Files          20       20              
  Lines        8952     8952              
==========================================
- Hits         3695     3692       -3     
- Misses       4087     4088       +1     
- Partials     1170     1172       +2     

see 2 files with indirect coverage changes