Update pyproject-fmt requirement from <1.9 to <2.1

Updates the requirements on [pyproject-fmt](https://github.com/tox-dev/pyproject-fmt) to permit the latest version.
- [Release notes](https://github.com/tox-dev/pyproject-fmt/releases)
- [Commits](tox-dev/pyproject-fmt@0.1.0...2.0.4)

---
updated-dependencies:
- dependency-name: pyproject-fmt
  dependency-type: direct:production
...

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

pyproject.toml

@@ -64,7 +64,7 @@ develop = [
   "black<25",
   "mypy<1.11",
   "poethepoet<1",
-  "pyproject-fmt<1.9",
+  "pyproject-fmt<2.1",
   "ruff<0.5",
   "validate-pyproject<0.17",
 ]