Bump ruamel-yaml from 0.18.5 to 0.18.6

Bumps [ruamel-yaml]() from 0.18.5 to 0.18.6.

---
updated-dependencies:
- dependency-name: ruamel-yaml
  dependency-type: indirect
  update-type: version-update:semver-patch
...

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