Bump pycparser from 2.18 to 2.19

Bumps [pycparser](https://github.com/eliben/pycparser) from 2.18 to 2.19.
- [Release notes](https://github.com/eliben/pycparser/releases)
- [Changelog](https://github.com/eliben/pycparser/blob/master/CHANGES)
- [Commits](eliben/pycparser@release_v2.18...release_v2.19)

Signed-off-by: dependabot[bot] <support@dependabot.com>

Author: dependabot-support

requirements/constraints.txt

@@ -15,7 +15,7 @@ jsonschema==2.6.0
 multidict==4.3.1
 nodeenv==1.3.2
 pre-commit==0.12.2
-pycparser==2.18
+pycparser==2.19
 PyMySQL==0.9.2
 PyYAML==3.13
 six==1.11.0