chore(deps-dev): Bump strict-kwargs from 2026.5.20 to 2026.6.4

Bumps [strict-kwargs](https://github.com/adamtheturtle/strict-kwargs) from 2026.5.20 to 2026.6.4.
- [Release notes](https://github.com/adamtheturtle/strict-kwargs/releases)
- [Changelog](https://github.com/adamtheturtle/strict-kwargs/blob/main/CHANGELOG.rst)
- [Commits](adamtheturtle/strict-kwargs@2026.5.20...2026.6.4)

---
updated-dependencies:
- dependency-name: strict-kwargs
  dependency-version: 2026.6.4
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

pyproject.toml

@@ -99,7 +99,7 @@ optional-dependencies.dev = [
     # ``sphinxcontrib-towncrier`` renders unreleased news fragments
     # into docs/source/unreleased.rst during Sphinx builds.
     "sphinxcontrib-towncrier==0.5.0a0",
-    "strict-kwargs==2026.5.20",
+    "strict-kwargs==2026.6.4",
     "sybil==10.0.1",
     "tenacity==9.1.4",
     "towncrier==25.8.0",