6.0.0

• Moved away from using enums for things like ProductType. This change was made to improve the maintainability of the library. This is potentially a breaking change. If you relied on the fact that those types were enums then your code will break. If not, then everything should still work the same. All public APIs are still called and used in the same way.
• Calling LegoGraphClient.authenticateAsync is now optional. If you don't call it, then it will be called for you the first time you try to query the graph and again if the authentication expires.
• Added new values for ProductType and ProductTheme.