Update pycparser to 2.19

[pyup-bot]

This PR updates pycparser from 2.18 to 2.19.

Changelog

2.19

- PR 277: Fix parsing of floating point literals
- PR 254: Add support for parsing empty structs
- PR 240: Fix enum formatting in generated C code (also 216)
- PR 222: Add support for pragma in struct declarations

Links

• PyPI: https://pypi.org/project/pycparser
• Changelog: https://pyup.io/changelogs/pycparser/
• Repo: https://github.com/eliben/pycparser