Bump diff-cover from 10.2.1 to 10.3.0

Bumps [diff-cover](https://github.com/Bachmann1234/diff-cover) from 10.2.1 to 10.3.0.
- [Release notes](https://github.com/Bachmann1234/diff-cover/releases)
- [Changelog](https://github.com/Bachmann1234/diff_cover/blob/main/CHANGELOG)
- [Commits](Bachmann1234/diff_cover@v10.2.1...v10.3.0)

---
updated-dependencies:
- dependency-name: diff-cover
  dependency-version: 10.3.0
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

pyproject.toml

@@ -61,7 +61,7 @@ statemachine_diagrams = [
 dev = [
     "pytest>=9.0.3",
     "pytest-cov>=5.0.0",
-    "diff-cover>=10.2.1",
+    "diff-cover>=10.3.0",
     "libcst>=0.4.0",
     "build>=1.5.0",
     "ruff>=0.15.14",