Remove frozen=True and slots=True from exceptions to avoid trigge…

…ring context manager traceback issue (#51)

stompman/errors.py

@@ -7,37 +7,37 @@
     from stompman.config import ConnectionParameters
 
 
-@dataclass(frozen=True, kw_only=True, slots=True)
+@dataclass(kw_only=True)
 class Error(Exception):
     def __str__(self) -> str:
         return self.__repr__()
 
 
-@dataclass(frozen=True, kw_only=True, slots=True)
+@dataclass(kw_only=True)
 class ConnectionLostError(Error):
     """Raised in stompman.AbstractConnection—and handled in stompman.ConnectionManager, therefore is private."""
 
 
-@dataclass(frozen=True, kw_only=True, slots=True)
+@dataclass(kw_only=True)
 class ConnectionConfirmationTimeoutError(Error):
     timeout: int
     frames: list[MessageFrame | ReceiptFrame | ErrorFrame | HeartbeatFrame]
 
 
-@dataclass(frozen=True, kw_only=True, slots=True)
+@dataclass(kw_only=True)
 class UnsupportedProtocolVersionError(Error):
     given_version: str
     supported_version: str
 
 
-@dataclass(frozen=True, kw_only=True, slots=True)
+@dataclass(kw_only=True)
 class FailedAllConnectAttemptsError(Error):
     servers: list["ConnectionParameters"]
     retry_attempts: int
     retry_interval: int
     timeout: int
 
 
-@dataclass(frozen=True, kw_only=True, slots=True)
+@dataclass(kw_only=True)
 class RepeatedConnectionLostError(Error):
     retry_attempts: int