0.320.2

This release fixes a bug where print_schema would emit a type definition
twice when the same type (for example an enum) was referenced both as a schema
directive field and elsewhere in the schema. The duplicated definition produced
invalid SDL that violates the GraphQL spec and is rejected by graphql-core's
build_schema.

For example, the following schema now prints enum Role only once:

import enum

import strawberry
from strawberry.schema_directive import Location


@strawberry.enum
class Role(enum.Enum):
    EDITOR = "editor"
    VIEWER = "viewer"


@strawberry.schema_directive(locations=[Location.FIELD_DEFINITION])
class RequiresRole:
    roles: list[Role]


@strawberry.type
class Query:
    secret: str = strawberry.field(directives=[RequiresRole(roles=[Role.EDITOR])])

    @strawberry.field
    def assign(self, role: Role) -> bool:
        return True

This release was contributed by @patrick91 in #4504