fix: conditionally add sign=False on dulwich>=0.24.3 (#458)

Author: skshetry

src/scmrepo/git/backend/dulwich/__init__.py

@@ -369,13 +369,18 @@ def _expand_paths(self, paths: list[str], force: bool = False) -> Iterator[str]:
                     yield rel
 
     def commit(self, msg: str, no_verify: bool = False):
+        from dulwich import __version__ as dulwich_version
         from dulwich.errors import CommitError
         from dulwich.porcelain import Error, TimezoneFormatError, commit
         from dulwich.repo import InvalidUserIdentity
 
+        commit_kwargs: dict[str, Any] = {}
+        if dulwich_version >= (0, 24, 3):
+            commit_kwargs["sign"] = False
+
         with reraise((Error, CommitError), SCMError("Git commit failed")):
             try:
-                commit(self.repo, message=msg, no_verify=no_verify, sign=False)
+                commit(self.repo, message=msg, no_verify=no_verify, **commit_kwargs)
             except InvalidUserIdentity as exc:
                 raise SCMError("Git username and email must be configured") from exc
             except TimezoneFormatError as exc: