CompatHelper: bump compat for InfiniteArrays in [extras] to 0.15, (keep existing compat)

[github-actions]

This pull request changes the compat entry for the InfiniteArrays package from 0.12, 0.13, 0.14 to 0.12, 0.13, 0.14, 0.15.
This keeps the compat entries for earlier versions.

Note: I have not tested your package with this new compat entry.
It is your responsibility to make sure that your package tests pass before you merge this pull request.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 89.99%. Comparing base (cb5f59c) to head (af0975a).
⚠️ Report is 2 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #492   +/-   ##
=======================================
  Coverage   89.99%   89.99%           
=======================================
  Files          27       27           
  Lines        3739     3739           
=======================================
  Hits         3365     3365           
  Misses        374      374           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.