Update cmake requirement from ~=4.2 to ~=4.3

Updates the requirements on [cmake](https://github.com/scikit-build/cmake-python-distributions) to permit the latest version.
- [Release notes](https://github.com/scikit-build/cmake-python-distributions/releases)
- [Changelog](https://github.com/scikit-build/cmake-python-distributions/blob/main/HISTORY.rst)
- [Commits](scikit-build/cmake-python-distributions@4.2.0...4.3.1)

---
updated-dependencies:
- dependency-name: cmake
  dependency-version: 4.3.1
  dependency-type: direct:development
...

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

Author: dependabot[bot]

pyproject.toml

@@ -7,7 +7,7 @@ backend-path = ["tools/pylib/_boutpp_build/"]
 
 [dependency-groups]
 dev = [
-     "cmake~=4.2",
+     "cmake~=4.3",
      "clang-format~=22.0",
      "clang-tidy~=22.0",
      "clangd~=22.0",