Bump nodemon from 2.0.19 to 2.0.20

Bumps [nodemon](https://github.com/remy/nodemon) from 2.0.19 to 2.0.20.
- [Release notes](https://github.com/remy/nodemon/releases)
- [Commits](https://github.com/remy/nodemon/compare/v2.0.19...v2.0.20)