omniauth-microsoft_graph vulnerable to account takeover (nOAuth)

omniauth-microsoft_graph provides an Omniauth strategy for the Microsoft Graph API. Prior to versions 2.0.0, the implementation did not validate the legitimacy of the `email` attribute of the user nor did it give/document an option to do so, making it susceptible to nOAuth misconfiguration in cases when the `email` is used as a trusted user identifier. This could lead to account takeover. Version 2.0.0 contains a fix for this issue.