Openstep-plist

- Dropped support for Python 3.7, added support for Python 3.12.
- Removed use of deprecated Py_UNICODE APIs.
- Also build wheels for Linux 64-bit ARM architecture (manylinux-aarch64)
- `__main__`: add options for indent level, pager and json output

- Build wheels for Python 3.11 and universal2 wheels for macOS with Apple Silicon. No code changes.

Replace use of `array.array` with C++ vector to make it work on pypy3 (12)
Added wheels for CPython 3.10 and for PyPy 3.7.

Add CPython 3.8 and 3.9 wheels, drop 2.7.

Write strings quoted if they can be confused with an integer or a float, or if they contain any characters that is not in the following set:


$.0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ_abcdefghijklmnopqrstuvwxyz

Reverted the default value of `use_numbers` to False in the parser's `load` and `loads` functions. So by default the parser will treat any plist string whether quoted or unquoted as a Python unicode string.

Set it to True to enable the feature whereby unquoted plist strings are attempted to be converted to Python int or float.