Update mkdocs-rss-plugin requirement from <0.22,>=0.20 to >=0.20,<1.17

Updates the requirements on [mkdocs-rss-plugin](https://github.com/Guts/mkdocs-rss-plugin) to permit the latest version.
- [Release notes](https://github.com/Guts/mkdocs-rss-plugin/releases)
- [Changelog](https://github.com/Guts/mkdocs-rss-plugin/blob/main/CHANGELOG.md)
- [Commits](Guts/mkdocs-rss-plugin@0.20.0...1.16.0)

---
updated-dependencies:
- dependency-name: mkdocs-rss-plugin
  dependency-type: direct:production
...

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

requirements.txt

@@ -19,4 +19,4 @@ mkdocs-git-revision-date-localized-plugin>=0.9,<1.1
 mkdocs-macros-plugin>=0.5,<0.7
 mkdocs-minify-plugin<0.6
 mkdocs-redirects<1.1
-mkdocs-rss-plugin>=0.20,<0.22
+mkdocs-rss-plugin>=0.20,<1.17