feat: add emit_str_enum config option

[devstein]

Description

Add emit_str_enum config option to change generate enums to use enum.StrEnum, which implements __str__ and string comparison checks for users.

New Behavior

with emit_str_enum

class Status(enum.StrEnum):
    """Venues can be either open or closed"""
    OPEN = "op!en"
    CLOSED = "clo@sed"

without emit_str_enum (current behavior)

class Status(str, enum.Enum):
    """Venues can be either open or closed"""
    OPEN = "op!en"
    CLOSED = "clo@sed"

Todos

• Add documentation
• Add tests