Update ovos-plugin-manager requirement in /requirements

Updates the requirements on [ovos-plugin-manager](https://github.com/OpenVoiceOS/OVOS-plugin-manager) to permit the latest version.
- [Release notes](https://github.com/OpenVoiceOS/OVOS-plugin-manager/releases)
- [Changelog](https://github.com/OpenVoiceOS/ovos-plugin-manager/blob/dev/CHANGELOG.md)
- [Commits](OpenVoiceOS/ovos-plugin-manager@0.1.1a1...0.2.0)

---
updated-dependencies:
- dependency-name: ovos-plugin-manager
  dependency-type: direct:production
...

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

requirements/requirements.txt

@@ -1,4 +1,4 @@
 ovos-utils~=0.0, >=0.0.38
 ovos-bus-client~=0.0, >=0.0.8
 ovos-config~=0.0,>=0.0.13
-ovos-plugin-manager~=0.0, >=0.0.26
+ovos-plugin-manager~=0.2