Fixed allocator which triggers a compilation error in clang 13.1.6

[pre-commit.ci] pre-commit autoupdate

Modernize

updates:
- [github.com/pre-commit/mirrors-clang-format: v14.0.4-1 → v14.0.6](https://github.com/pre-commit/mirrors-clang-format/compare/v14.0.4-1...v14.0.6)
- [github.com/psf/black: 22.3.0 → 22.6.0](https://github.com/psf/black/compare/22.3.0...22.6.0)

Remove std::unary_function

std::unary_function is deprecated since C++11 and removed in C++17

See: https://en.cppreference.com/w/cpp/utility/functional/unary_function

[pre-commit.ci] pre-commit autoupdate

updates:
- [github.com/pre-commit/mirrors-clang-format: v13.0.1 → v14.0.4-1](https://github.com/pre-commit/mirrors-clang-format/compare/v13.0.1...v14.0.4-1)
- [github.com/pre-commit/pre-commit-hooks: v4.2.0 → v4.3.0](https://github.com/pre-commit/pre-commit-hooks/compare/v4.2.0...v4.3.0)

for more information, see https://pre-commit.ci

format

Format: yapf 0.32

[cmake] Improve Eigen detection

- Avoid CMAKE_PACKAGE_REGISTRY
- Use Eigen3::Eigen if available

format