Specify encoding in Commit.trailer_list.

Author: itsluketwist

git/objects/commit.py

@@ -372,7 +372,7 @@ def trailers_list(self) -> List[Tuple[str, str]]:
         """
         cmd = ["git", "interpret-trailers", "--parse"]
         proc: Git.AutoInterrupt = self.repo.git.execute(cmd, as_process=True, istream=PIPE)  # type: ignore
-        trailer: str = proc.communicate(str(self.message).encode())[0].decode()
+        trailer: str = proc.communicate(str(self.message).encode())[0].decode("utf8")
         trailer = trailer.strip()
 
         if not trailer: