Bump pip from 19.1.1 to 19.2.1
Bump pip from 19.1.1 to 19.2.1

Bumps [pip](https://github.com/pypa/pip) from 19.1.1 to 19.2.1.
- [Release notes](https://github.com/pypa/pip/releases)
- [Changelog](https://github.com/pypa/pip/blob/master/NEWS.rst)
- [Commits](https://github.com/pypa/pip/commits)

Signed-off-by: dependabot-preview[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@dependabot.com>
camptocamp/ngeo,camptocamp/ngeo,camptocamp/ngeo,camptocamp/ngeo,camptocamp/ngeo