fix(changelog): allow --no-incremental to override changelog_incremental config

The "Bump version" workflow's release-notes step runs
`cz changelog --dry-run "${NEW_VERSION}"`, passing the new version as a
positional rev_range. Since pyproject.toml sets `changelog_incremental = true`
(#2074), this combination now always raises
"--incremental cannot be combined with a rev_range", failing every release.

There was previously no way to override a config-enabled
`changelog_incremental` back to false from the CLI, since `--incremental` was
a plain store_true flag defaulting to False.

- Change `--incremental` to use argparse.BooleanOptionalAction (default None),
  adding a `--no-incremental` flag.
- CLI flag now takes precedence over the `changelog_incremental` config
  setting; falls back to config only when neither flag is passed.

Note: `.github/workflows/bumpversion.yml` still needs to be updated to pass
`--no-incremental` in its release-notes step, but that change requires the
`workflow` OAuth scope and is left for a follow-up/maintainer to apply.

`cz bump`'s internal changelog call already hardcodes incremental=True, so it
is unaffected by this change.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: bearomorphism

commitizen/cli.py

@@ -413,11 +413,13 @@ def __call__(
                     },
                     {
                         "name": "--incremental",
-                        "action": "store_true",
-                        "default": False,
+                        "action": argparse.BooleanOptionalAction,
+                        "default": None,
                         "help": (
                             "Generate changelog from the last created version, "
-                            "useful if the changelog has been manually modified."
+                            "useful if the changelog has been manually modified. "
+                            "Use `--no-incremental` to override a `changelog_incremental` "
+                            "setting enabled in the configuration."
                         ),
                     },
                     {

commitizen/commands/changelog.py

@@ -32,7 +32,7 @@ class ChangelogArgs(TypedDict, total=False):
     current_version: str
     dry_run: bool
     file_name: str | None
-    incremental: bool
+    incremental: bool | None
     merge_prerelease: bool
     rev_range: str
     start_rev: str
@@ -78,9 +78,16 @@ def __init__(self, config: BaseConfig, arguments: ChangelogArgs) -> None:
 
         self.changelog_format = get_changelog_format(self.config, self.file_name)
 
-        self.incremental = bool(
-            arguments.get("incremental")
-            or self.config.settings.get("changelog_incremental")
+        # `--incremental`/`--no-incremental` on the CLI always takes precedence over
+        # the `changelog_incremental` setting. When neither flag is passed, the
+        # argument is `None` and we fall back to the config value. This lets a
+        # one-off invocation (e.g. `cz changelog <rev_range>`) opt out of an
+        # incremental default enabled in the configuration.
+        incremental_arg = arguments.get("incremental")
+        self.incremental = (
+            incremental_arg
+            if incremental_arg is not None
+            else bool(self.config.settings.get("changelog_incremental"))
         )
         self.dry_run = bool(arguments.get("dry_run"))