v3.3.3: Fix windows-2022 wheels & MANIFEST.in warnings (#388)

What's Changed

• Add Vasculature section_offsets & section_connectivity by @eleftherioszisis in #352
• Add n_points methods for immutable Morphology & Vasculature by @eleftherioszisis in #359
• Update pybind11 version to v2.8.1 release by @eleftherioszisis in #362
• add isHeterogeneous for checking if neurites are mixed
• fix operator<< instances by @mgeplf in #364
• Update readthedocs python to 3.9 by @eleftherioszisis in #365
• Add section type exception for unsupported type in ascii writer by @eleftherioszisis in #370
• Have Section and MitoSection have value semantics for comparison by @mgeplf in #379
• dependencies: allow to use an external pybind11. by @matz-e in #351
• Handle missmatching soma pts diameters in swc/asc by @eleftherioszisis in #385
• Catch2: move to submodule and update to v2.13.8 by @matz-e in #386

Full Changelog: v3.3.2...v3.3.3