Feature/issue 270 provide numerical output where zero means no differences found

[danielfromearth]

GitHub Issue: #270

Description

This change makes it so there is a return value from the ncompare.compare function. The return value represents the total number of differences found (across variables, groups, and attributes). This enables for ncompare.compare to be used as a quick check, with ncompare.compare(file_1, file_2) == 0 representing no structural differences discovered between two netCDF files.

Local test steps

All tests passed.

PR Acceptance Checklist

• Unit tests added/updated and passing.
• [n/a] Integration testing
• CHANGELOG.md updated
• Documentation updated (if needed).

---

📚 Documentation preview 📚: https://ncompare--278.org.readthedocs.build/en/278/

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 92.30%. Comparing base (6ebaafa) to head (302c7be).
Report is 9 commits behind head on develop.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop     #278      +/-   ##
===========================================
+ Coverage    92.18%   92.30%   +0.12%     
===========================================
  Files            5        6       +1     
  Lines          435      442       +7     
===========================================
+ Hits           401      408       +7     
  Misses          34       34              

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