Add skimage requirement for CIL-Demos

[lauramurgatroyd]

Description

Add requirement of skimage to CIL-Demos install instructions

Required for the new callbacks notebook

Example Usage

Changes

Testing you performed

Please add any demo scripts to https://github.com/TomographicImaging/CIL-Demos/tree/main/misc

Related issues/links

Closes #1956

Checklist

• I have performed a self-review of my code
• I have added docstrings in line with the guidance in the developer guide
• I have updated the relevant documentation
• I have implemented unit tests that cover any new or modified functionality
• CHANGELOG.md has been updated with any functionality change
• Request review from all relevant developers
• Change pull request label to 'Waiting for review'

Contribution Notes

Please read and adhere to the developer guide and local patterns and conventions.

• The content of this Pull Request (the Contribution) is intentionally submitted for inclusion in CIL (the Work) under the terms and conditions of the Apache-2.0 License
• I confirm that the contribution does not violate any intellectual property rights of third parties

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[casperdcl]

This is exceptionally bad practice to put requirements in CIL that have nothing to do with CIL (they are not dependencies).

Please put things in CIL-Demos instead.

At most you could put them in CIL's requirements-test (but not readme etc.) clearly commenting that they're there due to CIL-Demos /cc @paskino

[MargaretDuff]

I think the point was that the docker image will need to have tomopy and scikit-image installed. It uses requirements-test.yml. It has scikit-image but not tomopy.

[casperdcl]

Exactly. The ONLY correct way to do this is:

1. drop this entire PR
2. open another PR to remove all the other cruft from README & requirements-test.yml
3. open a PR on CIL-Demos & CIL-User-Showcase adding root environment.yml
4. open a PR on CIL to make the Dockerfile use conda install -n base --file=https://raw.githubusercontent.com/TomographicImaging/CIL-{Demos,User-Showcase}/refs/heads/main/environment.yml
   • @paskino is well aware of this strategy in SyneRBI/SIRF-SuperBuild:docker/user_demos.sh :)

[lauramurgatroyd]

Tomopy is no longer required so updating this PR to just add skimage to the CIL-Demos install instructions and I will open another issue with Casper's suggetions

[lauramurgatroyd]

@casperdcl thanks for your suggestions, hopefully this covers everything: #1961

We need a wider discussion / agreement before removing the CIL-Demos install instructions from the CIL readme, so I still need to add skimage to the install instructions in this PR

[MargaretDuff]

Thanks @lauramurgatroyd

[hrobarts]

Looks good

Have implemented Casper's suggestions