Postpone Python 3.10 dataclass features

pyproject.toml

@@ -5,6 +5,7 @@ build-backend = "setuptools.build_meta"
 [project]
 name = "changelist"
 version = "0.5rc0.dev0"
+# TODO add slots=True, kw_only=True to dataclasses starting with >=3.10
 requires-python = ">=3.9"
 readme = "README.md"
 license = {file = "LICENSE.txt"}

src/changelist/_format.py

@@ -11,7 +11,7 @@
 logger = logging.getLogger(__name__)
 
 
-@dataclass(frozen=True, slots=True, kw_only=True)
+@dataclass(frozen=True)
 class ChangeNote:
     """Describes an atomic change in the notes."""
 
@@ -65,7 +65,7 @@ def from_pull_requests(
         return notes
 
 
-@dataclass(frozen=True, slots=True, kw_only=True)
+@dataclass(frozen=True)
 class Contributor:
     """A person mentioned in the notes as an author or reviewer.
 
@@ -74,7 +74,7 @@ class Contributor:
      contributor's GitHub profile.
     """
 
-    name: str | None
+    name: str
     login: str
     reference_url: str
 
@@ -98,7 +98,7 @@ def from_named_users(cls, named_users: set[NamedUser]) -> "set[Contributor]":
         return contributors
 
 
-@dataclass(frozen=True, kw_only=True)
+@dataclass(frozen=True)
 class MdFormatter:
     """Format release notes in Markdown from PRs, authors and reviewers."""