Add ESMValTool ENSO diagnostics

[bouweandela]

Description

Add ESMValTool ENSO diagnostics

Sample data available in Climate-REF/ref-sample-data#37

Closes #225

Checklist

Please confirm that this pull request has done the following:

• Tests added
• Documentation added (where applicable)
• Changelog item added to changelog/

[bouweandela]

At least some of the test failures are because I had to use a newer version of ESMValTool. I opened #325 to update ESMValTool. It would be great if we could get that merged first.

[bouweandela]

I've updated the hashes of the recipes, but this may invalidate the regression tests until #325 has been merged. The tests also require a new release of the sample data that includes Climate-REF/ref-sample-data#37.

[codecov]

Codecov Report

❌ Patch coverage is 97.77778% with 1 line in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
packages/climate-ref/src/climate_ref/testing.py	0.00%	1 Missing ⚠️

Files with missing lines	Coverage Δ
...src/climate_ref_esmvaltool/diagnostics/__init__.py	100.00% <100.00%> (ø)
...ool/src/climate_ref_esmvaltool/diagnostics/base.py	100.00% <100.00%> (ø)
...ool/src/climate_ref_esmvaltool/diagnostics/enso.py	100.00% <100.00%> (ø)
...ckages/climate-ref/src/climate_ref/cli/datasets.py	96.55% <ø> (ø)
packages/climate-ref/src/climate_ref/testing.py	63.26% <0.00%> (ø)

🚀 New features to boost your workflow:

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

[bouweandela]

@lewisjared This is now up to date with the latest version of the sample data, so should be ready to merge