Move developers' conda yml to environment.yml

[rcomer]

Description

Closes #7205, since it has two 👍 and no objections.

I see you have move the furniture around since my last PR 👀 😆

Checklist

Important

The Iris core developers are here to help! If anything below is unclear, just post a comment asking for help 😊

• Included a What's New entry
• Incorporated type hints in any changed code
• Checked if tests need updating
• Checked if benchmarks need updating
• Checked if documentation needs updating
  • Docstrings (we love code examples!)
  • User Manual pages
• Checked if dependencies need updating
• Confirmed that the GitHub 'checks' on this PR are passing ✅
  (further reading)

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[scitools-ci]

Templating

This PR includes changes that may be worth sharing via templating. For each file listed below, please either:

• Action the suggestion via a pull request editing/adding the relevant file in the SciTools/.github templates/ directory. ¹
• Raise an issue against the SciTools/.github repo for the above action if you really don't have 10mins spare right now. Include an assignee, to avoid it being forgotten.
• Dismiss the suggestion if the changes are not suitable for templating.

You will need to dismiss this review before this PR can be merged. Recommend the reviewer does this as their final action before merging, as this text will continually update as commits come in.

Template candidates

The following changed files are not currently templated, but their parent directories suggest they may be good candidates for a new template to be created:

• AGENTS.md
• environment.yml

Footnotes

1. Include this text in the PR body to avoid any notifications about applying the template changes back to the source repo!
   @scitools-templating: please no update notification on: iris ↩

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.42%. Comparing base (d9ebbaf) to head (3056567).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #7267   +/-   ##
=======================================
  Coverage   90.42%   90.42%           
=======================================
  Files          93       93           
  Lines       25816    25816           
  Branches     4796     4796           
=======================================
  Hits        23344    23344           
  Misses       1693     1693           
  Partials      779      779           

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[rcomer]

I think all the CI failures are due to requirements/readthedocs.yml now being a broken symbolic link. Is there a reason RTD has its own symbolic link or could we point directly at environment.yml here?

iris/.readthedocs.yml

Line 22 in d9ebbaf

environment: requirements/readthedocs.yml