aiida-orca version not updated in aiida plugin registry

I noticed that the aiida plugin registry still points to version 0.5.1 as the latest version.

https://aiidateam.github.io/aiida-registry/plugins/aiida-orca.html

I suspect that it is because the registry is pointing to the master branch that hasn't been updated. I guess we can either:

- merge develop to master branch
- change the branch in the aiida plugin registry.