Convert Connection to a dataclass

All other classes are dataclasses, so it is better for consistency.

Signed-off-by: Leandro Lucarella <[email protected]>

Author: llucax

src/frequenz/client/microgrid/_connection.py

@@ -3,10 +3,12 @@
 
 """Defines the connections between microgrid components."""
 
-from typing import NamedTuple
 
+from dataclasses import dataclass
 
-class Connection(NamedTuple):
+
+@dataclass(frozen=True)
+class Connection:
     """Metadata for a connection between microgrid components."""
 
     start: int