Add changelog project URL for PyPI

[scop]

What do these changes do?

Add a changelog link to package metadata so that PyPI shows a direct link to it from the project page.

Are there changes in behavior for the user?

N/A

Related issue number

Checklist

• I think the code is well written
• Unit tests for the changes exist
• Documentation reflects the changes
• Add a new news fragment into the CHANGES folder
  • name it <issue_id>.<type> (e.g. 588.bugfix)
  • if you don't have an issue_id change it to the pr id after creating the PR
  • ensure type is one of the following:
    • .feature: Signifying a new feature.
    • .bugfix: Signifying a bug fix.
    • .doc: Signifying a documentation improvement.
    • .removal: Signifying a deprecation or removal of public API.
    • .misc: A ticket has been closed, but it is not of interest to users.
  • Make sure to use full sentences with correct case and punctuation, for example: Fix issue with non-ascii contents in doctest text files.

[codecov]

Codecov Report

Merging #877 (b4ea98a) into master (723a5ba) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #877   +/-   ##
=======================================
  Coverage   99.74%   99.74%           
=======================================
  Files           4        4           
  Lines         772      772           
  Branches      219      219           
=======================================
  Hits          770      770           
  Misses          2        2           

Flag	Coverage Δ
unit	99.61% <ø> (ø)

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