Update dependencies to resolve OCP load error (#173)

# Description
Pin maximum ovos-plugin-manager version to resolve load error with
stable OCP

# Issues
Patch to workaround
OpenVoiceOS/ovos-plugin-manager#229

# Other Notes
<!-- Note any breaking changes, WIP changes, requests for input, etc.
here -->

Co-authored-by: Daniel McKnight <[email protected]>

requirements/requirements.txt

@@ -3,7 +3,7 @@ ovos-utils>=0.0.35,<0.2.0
 ovos-config~=0.0.10
 phoneme-guesser~=0.1
 # TODO: Alpha patching ovos-audio dependency resolution
-ovos-plugin-manager~=0.0.24,>=0.0.26a16
+ovos-plugin-manager~=0.0.24,>=0.0.26a16,<0.0.26a21
 neon-utils[network]~=1.9
 click~=8.0
 click-default-group~=1.2