Update js-yaml to v3.13.1 (#151)

A security vulnerability was found in js-yaml; the CLI doesn't
use the affected method but out of an abundance of caution we
can upgrade anyway.

Author: Matt Willer

package-lock.json

@@ -36,7 +36,7 @@
 		"debug": "^4.1.0",
 		"fs-extra": "^7.0.0",
 		"inquirer": "^6.2.0",
-		"js-yaml": "^3.12.0",
+		"js-yaml": "^3.13.1",
 		"lodash": "^4.17.11",
 		"ora": "^3.0.0",
 		"p-event": "^2.3.1"