Start 2.3.0-dev0 🎉

[IAlibay]

Changes made in this Pull Request:

• Started new changelog entry set
• Updated versions

PR Checklist

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

[codecov]

Codecov Report

Merging #3697 (7e91dab) into develop (eab18cb) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff            @@
##           develop    #3697   +/-   ##
========================================
  Coverage    94.35%   94.35%           
========================================
  Files          191      191           
  Lines        24975    24975           
  Branches      3365     3365           
========================================
  Hits         23565    23565           
  Misses        1362     1362           
  Partials        48       48           

Impacted Files	Coverage Δ
package/MDAnalysis/version.py	100.00% <100.00%> (ø)

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[IAlibay]

@MDAnalysis/coredevs simple enough one to review if someone can give this a thumbs up that'd be great. You can see how it was done for 2.1.0 here if you want to compare: #3400

[hmacdope]

LGTM

[orbeckst]

LGTM.

You could fix the CHANGELOG #3696 here, too.

[IAlibay]

LGTM.

You could fix the CHANGELOG #3696 here, too.

To avoid re-running CI I'll deal with that with the deploy PR.