EigenPy 3.1.0

What's Changed

• [pre-commit.ci] pre-commit autoupdate by @pre-commit-ci in #362
• Sync submodule cmake by @jcarpent in #363
• [pre-commit.ci] pre-commit autoupdate by @pre-commit-ci in #366
• WIP: Expose boost::none_t type (and std::nullopt_t when available) by @ManifoldFR in #367
• optional: check registration of none type and optional type before exposing converter by @ManifoldFR in #368
• [pre-commit.ci] pre-commit autoupdate by @pre-commit-ci in #371
• Sync submodule CMake by @jcarpent in #373

Full Changelog: v3.0.0...v3.1.0