Bump imageio from 2.19.2 to 2.19.3 in /requirements (#1145)

Bumps [imageio](https://github.com/imageio/imageio) from 2.19.2 to 2.19.3.
- [Release notes](https://github.com/imageio/imageio/releases)
- [Changelog](https://github.com/imageio/imageio/blob/master/CHANGELOG.md)
- [Commits](imageio/imageio@v2.19.2...v2.19.3)

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

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

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

Author: dependabot[bot]

requirements/requirements_docs.txt

@@ -1,7 +1,7 @@
 Sphinx==4.5.0
 ansys-mapdl-reader==0.51.14
 imageio-ffmpeg==0.4.7
-imageio==2.19.2
+imageio==2.19.3
 jupyter_sphinx==0.3.2
 jupyterlab>=3.2.8
 matplotlib==3.5.2