Build in parallel

Update version number

Update dev dependencies

Update version number

Merge pull request #62 from Kijewski/pr-issue-61

 Fix typing for _SupportsWrite

Update to Unicode 15.0.0 (#48)

Fix PEP 517 build

Cannot compile manylinux1 libs for Python 3.10

RTD selects the wrong docutils version

Use filenames with extensions

The filename "VERSION" may clash with the C++ header file "<version>"
that was added in C++20 for case insensitive filesystems.

This PR adds extensions to "src/VERSION" and "src/DESCRIPTION".

Also fast_double_parser in updated to v0.5.0.