Update names to match new version of Oceananigans

[tomchor]

CliMA/Oceananigans.jl#4046 (released with Oceananigans version 0.96) introduced new default names for the dimensions. This PR updates pynanigans to account for that.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 83.33333% with 3 lines in your changes missing coverage. Please review.

Project coverage is 76.23%. Comparing base (c1e8dd6) to head (cc3030d).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
pynanigans/utils.py	50.00%	2 Missing ⚠️
pynanigans/grids.py	91.66%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##             main       #5       +/-   ##
===========================================
+ Coverage   63.15%   76.23%   +13.07%     
===========================================
  Files           4        4               
  Lines         114      101       -13     
===========================================
+ Hits           72       77        +5     
+ Misses         42       24       -18     

☔ 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.