Fix #110 - Add **kwargs passthrough on CUD mutations, enables "description" annotation from Strawberry.

[JoeWHoward]

You may now use the "description" kwarg in any of the CUD mutations to utilize Strawberry's annotations.

Example:

@strawberry.type
class Mutation:
    createTag: Tag = mutations.create(TagInput, description="Create a tag with title and description.")

Note: Using **kwargs here may have unintended consequences, but all the tests passed.

[bellini666]

LGTM! Thanks for the contribution :)