Fix js-yaml tags for v4.0.0+

Repair backwards compatibility https://github.com/nodeca/js-yaml/blob/master/migrate_v3_to_v4.md
with a bunch of plugins that use these yaml tags.

e.g.: https://github.com/lavas-project/hexo-pwa#options uses these yaml tags in the routes `!!js/regexp`

lib/plugins/renderer/yaml.js

@@ -1,10 +1,11 @@
-'use strict';
+"use strict";
 
-const yaml = require('js-yaml');
-const { escape } = require('hexo-front-matter');
+const yaml = require("js-yaml");
+const { escape } = require("hexo-front-matter");
+const schema = yaml.DEFAULT_SCHEMA.extend(require("js-yaml-js-types").all);
 
 function yamlHelper(data) {
-  return yaml.load(escape(data.text));
+  return yaml.load(escape(data.text), { schema });
 }
 
 module.exports = yamlHelper;

package.json

@@ -49,6 +49,7 @@
     "hexo-log": "^3.0.0",
     "hexo-util": "^2.4.0",
     "js-yaml": "^4.0.0",
+    "js-yaml-js-types": "^1.0.0",
     "micromatch": "^4.0.2",
     "moize": "^6.1.0",
     "moment": "^2.22.2",