Tie off 2.7.0, add release upper pin (numpy)

[IAlibay]

Towards #4382

Changes made in this Pull Request:

• Set version numbers of 2.7.0
• Add upper pin for numpy in pyproject.toml
• Tie off the changelog

PR Checklist

• Tests?
• Docs?
• CHANGELOG updated?
• Issue raised/referenced?

Developers certificate of origin

• I certify that this contribution is covered by the LGPLv2.1+ license as defined in our LICENSE and adheres to the Developer Certificate of Origin.

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📚 Documentation preview 📚: https://mdanalysis--4389.org.readthedocs.build/en/4389/

[github-actions]

Linter Bot Results:

Hi @IAlibay! Thanks for making this PR. We linted your code and found the following:

There are currently no issues detected! 🎉

[fiona-naughton]

lgtm 👍

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (770a577) 93.39% compared to head (550329c) 93.41%.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #4389      +/-   ##
===========================================
+ Coverage    93.39%   93.41%   +0.01%     
===========================================
  Files          171      185      +14     
  Lines        22511    23625    +1114     
  Branches      4129     4129              
===========================================
+ Hits         21025    22069    +1044     
- Misses         965     1036      +71     
+ Partials       521      520       -1     

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