Update scikit-image requirement (#855)

Updates the requirements on [scikit-image](https://github.com/scikit-image/scikit-image) to permit the latest version.
- [Release notes](https://github.com/scikit-image/scikit-image/releases)
- [Changelog](https://github.com/scikit-image/scikit-image/blob/main/RELEASE.txt)
- [Commits](scikit-image/scikit-image@v0.14.2...v0.22.0)

---
updated-dependencies:
- dependency-name: scikit-image
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

setup.py

@@ -55,7 +55,7 @@ def readme():
         "Pillow>=5.4.1, <11.0.0",
         "opencv-python>=3.2.0, <5.0.0",
         "scipy>=1.3.0, <2.0.0",
-        'scikit-image>=0.14.2, !=0.17.1, <0.22',  # https://github.com/SeldonIO/alibi/issues/215
+        'scikit-image>=0.14.2, !=0.17.1, <0.23',  # https://github.com/SeldonIO/alibi/issues/215
         "scikit-learn>=0.20.2, <2.0.0",
         "transformers>=4.0.0, <5.0.0",
         "dill>=0.3.0, <0.4.0",