Bump js-yaml from 3.12.0 to 3.13.1 (#61)

Bumps [js-yaml](https://github.com/nodeca/js-yaml) from 3.12.0 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](nodeca/js-yaml@3.12.0...3.13.1)

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

yarn.lock

@@ -999,8 +999,8 @@ jade@0.26.3:
     mkdirp "0.3.0"
 
 js-yaml@^3.2.5:
-  version "3.12.0"
-  resolved "https://registry.yarnpkg.com/js-yaml/-/js-yaml-3.12.0.tgz#eaed656ec8344f10f527c6bfa1b6e2244de167d1"
+  version "3.13.1"
+  resolved "https://registry.yarnpkg.com/js-yaml/-/js-yaml-3.13.1.tgz#aff151b30bfdfa8e49e05da22e7415e9dfa37847"
   dependencies:
     argparse "^1.0.7"
     esprima "^4.0.0"