Bump ruamel-yaml from 0.15.42 to 0.17.21

Bumps [ruamel-yaml](https://sourceforge.net/p/ruamel-yaml/code/ci/default/tree) from 0.15.42 to 0.17.21.

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

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

pyproject.toml

@@ -21,7 +21,7 @@ classifiers=[
     "Topic :: Games/Entertainment :: Arcade"
     ]
 dependencies = [
-    "ruamel.yaml == 0.15.42",  # 0.15.x newer than this requires compiled c lib, currently no Mac arm versions, 0.16+ require code refactor
+    "ruamel.yaml == 0.17.21",  # 0.15.x newer than this requires compiled c lib, currently no Mac arm versions, 0.16+ require code refactor
     "mpf >= 0.56.0",  # Jan 15, 2023, our intention is for MPF-MC 0.56 to also work with MPF 0.57+
     "kivy == 2.1.0",  # Mar 6, 2022
     "psutil == 5.9.4",  # Nov 7, 2022