Bump imageio from 2.21.1 to 2.22.0 (#158)

Bumps [imageio](https://github.com/imageio/imageio) from 2.21.1 to 2.22.0.
- [Release notes](https://github.com/imageio/imageio/releases)
- [Changelog](https://github.com/imageio/imageio/blob/master/CHANGELOG.md)
- [Commits](imageio/imageio@v2.21.1...v2.22.0)

---
updated-dependencies:
- dependency-name: imageio
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

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

requirements/requirements_docs.txt

@@ -1,5 +1,5 @@
 pypandoc==1.8.1
-imageio==2.21.1
+imageio==2.22.0
 numpydoc==1.4.0
 imageio-ffmpeg==0.4.7
 Sphinx==5.1.1