Bump js-yaml from 3.11.0 to 3.13.1 in /example (#67)

Bumps [js-yaml](https://github.com/nodeca/js-yaml) from 3.11.0 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](https://github.com/nodeca/js-yaml/compare/3.11.0...3.13.1)

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

example/yarn.lock

@@ -1872,8 +1872,8 @@ esprima@^3.1.3:
   resolved "https://registry.yarnpkg.com/esprima/-/esprima-3.1.3.tgz#fdca51cee6133895e3c88d535ce49dbff62a4633"
 
 esprima@^4.0.0:
-  version "4.0.0"
-  resolved "https://registry.yarnpkg.com/esprima/-/esprima-4.0.0.tgz#4499eddcd1110e0b218bacf2fa7f7f59f55ca804"
+  version "4.0.1"
+  resolved "https://registry.yarnpkg.com/esprima/-/esprima-4.0.1.tgz#13b04cdb3e6c5d19df91ab6987a8695619b0aa71"
 
 estraverse@^4.2.0:
   version "4.2.0"
@@ -3161,8 +3161,8 @@ js-tokens@^3.0.0, js-tokens@^3.0.2:
   resolved "https://registry.yarnpkg.com/js-tokens/-/js-tokens-3.0.2.tgz#9866df395102130e38f7f996bceb65443209c25b"
 
 js-yaml@^3.7.0:
-  version "3.11.0"
-  resolved "https://registry.yarnpkg.com/js-yaml/-/js-yaml-3.11.0.tgz#597c1a8bd57152f26d622ce4117851a51f5ebaef"
+  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"