post https://go.v7labs.com/api/workspaces//projects//invitations
Creates a new invitation into a Project. The invitation will be sent to the email address provided.
Invitation will also add the user to the parent workspace with the role reader.
If the invitation is already pending or expired for this email/project combo,
if will be updated with the new role and resend.
Note: project_id is the same as agent_id
Callback