ilamb3 integration

[nocollier]

Description

An alternative integration through ilamb3.

Checklist

Please confirm that this pull request has done the following:

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

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Files with missing lines	Coverage Δ
...trics-ilamb/src/cmip_ref_metrics_ilamb/__init__.py	100.00% <100.00%> (ø)
...etrics-ilamb/src/cmip_ref_metrics_ilamb/example.py	100.00% <100.00%> (ø)

... and 3 files with indirect coverage changes

[nocollier]

@lewisjared Closed #63 in favor of this ILAMB integration, ready for you to take a look. I am on to additional metrics.

[lewisjared]

Thanks! LGTM.

I've assigned this to you. The typical flow that I use for merging is that the person who the PR is assigned to does the merging when ready. I find this workflow works well with a distributed team. Often I might assign a PR to the reviewer so that they can review (potentially fix) and merge if they are happy, hopefully skipping another day of back and forward if tiny fixes are needed.