Add changelog and source code URI to gemspec

[zirni]

Summary

Add metadata fields to make it easier for tools like Dependabot and Depfu to locate the changelog and source repository.

Checklist

The following are mandatory for all PRs:

• I agree that my PR will be published under the same license as Solidus.
• I have written a thorough PR description.
• I have kept my commits small and atomic.
• I have localized any and all user-facing strings that I added to the source code.
• I have used clear, explanatory commit messages.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 89.45%. Comparing base (2768bad) to head (f3d555c).
⚠️ Report is 26 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #6364   +/-   ##
=======================================
  Coverage   89.45%   89.45%           
=======================================
  Files         973      973           
  Lines       20314    20314           
=======================================
  Hits        18172    18172           
  Misses       2142     2142           

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[tvdeyen]

Thanks. I thin kit makes sense to have these in the sub gems gemspecs as well

[solidus-bot]

💚 All backports created successfully

Status	Branch	Result
✅	v4.6

Questions ?

Please refer to the Backport tool documentation and see the Github Action logs for details