Js2xml

What's Changed
- Add official Python 3.9 and 3.10 support, drop Python 2.7 support, remove `six` dependency
- Support a class call without parameters (e.g. `new Map`)
- Updated the CI setup


**Full Changelog**: https://github.com/scrapinghub/js2xml/compare/v0.4.0...v0.5.0

- Add Python 3.7 and 3.8 support, drop Python 3.4 support

- Use `calmjs.parse` instead of `slimit` for JavaScript parsing

[`calmjs.parse`](https://github.com/calmjs/calmjs.parse) is a well-maintained
fork of [`slimit`](https://github.com/rspivak/slimit) which solves some of
its shortcomings, such as support for JavaScript keywords being used as
object keys.

However, `calmjs.parse` also introduces slight changes to the output of
js2xml, making this change backward-incompatible.

- Fix unicode surrogate pair handling

- Code cleanup for Python 3

Distribute as universal wheel

- Python 3 support (tested with 3.4 and 3.5)
- Use logger to suppress Yacc warnings
- require PLY > 3.6
- Use bumpversion for versioning
- Pretty-print output is now a Unicode string

- Profiling scripts added
- Updated notes with use-case, installing via pip
- Force PLY 3.4 (3.6 has issues with slimit)

- Fix parsing of objects with integer keys
- Fix try/catch/finally and named function expressions
- Add download URL in setup file (for PyPI)