Allow square-brackets access to dataset objects

[MarkBlyth]

Minor fix. PyBOP Dataset class does not currently have a getitem, whereas parts of PyBOP (eg. base_model.py, line 124) attempt to use getitem, which throws an exception.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (3e78e24) 94.26% compared to head (b459cec) 94.59%.
Report is 59 commits behind head on develop.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop     #182      +/-   ##
===========================================
+ Coverage    94.26%   94.59%   +0.33%     
===========================================
  Files           35       40       +5     
  Lines         1325     1758     +433     
===========================================
+ Hits          1249     1663     +414     
- Misses          76       95      +19     

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

[NicolaCourtier]

Hi Mark, great suggestion - I've implemented something similar in PR #178, but I'm happy for this to be a separate PR as well.

[BradyPlanden]

Hi Mark,

Thanks for this addition! To merge this, can you please add an entry to the CHANGELOG.md, as well as update the tests to get the coverage passing. Once that's sorted feel free to request a review from either myself, Nicola, or Martin. It's good to go through this process even on the small PR's.

I've opened an issue (#185) to formalise this process for new developers so thanks for prompting that!

[BradyPlanden]

LGTM, thanks for the addition! Feel free to merge when you are ready.