marshmallow==2.19.0
pyyaml==3.13
sphinx==1.8.5
sphinx-issues==1.2.0
sphinx-rtd-theme==0.4.3

marshmallow==2.19.0
pyyaml==5.1
sphinx==1.8.5
sphinx-issues==1.2.0
sphinx-rtd-theme==0.4.3

Bump pyyaml from 3.13 to 5.1
[Security] Bump pyyaml from 3.13 to 5.1

Bumps [pyyaml](https://github.com/yaml/pyyaml) from 3.13 to 5.1. **This update includes security fixes.**
- [Release notes](https://github.com/yaml/pyyaml/releases)
- [Changelog](https://github.com/yaml/pyyaml/blob/master/CHANGES)
- [Commits](https://github.com/yaml/pyyaml/compare/3.13...5.1)

Signed-off-by: dependabot[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@dependabot.com>