Bump js-yaml from 3.9.1 to 3.13.1 in /src/LondonTravel.Site
Bump js-yaml from 3.9.1 to 3.13.1 in /src/LondonTravel.Site

Bumps [js-yaml](https://github.com/nodeca/js-yaml) from 3.9.1 to 3.13.1.
- [Release notes](https://github.com/nodeca/js-yaml/releases)
- [Changelog](https://github.com/nodeca/js-yaml/blob/master/CHANGELOG.md)
- [Commits](https://github.com/nodeca/js-yaml/compare/3.9.1...3.13.1)
martincostello/alexa-london-travel-site,martincostello/alexa-london-travel-site,martincostello/alexa-london-travel-site,martincostello/alexa-london-travel-site