add missing directive

lib/single-file/single-file-core.js

@@ -497,7 +497,7 @@ class Processor {
 		if (this.options.insertMetaCSP) {
 			const metaTag = this.doc.createElement("meta");
 			metaTag.httpEquiv = "content-security-policy";
-			metaTag.content = "default-src 'none'; font-src 'self' data:; img-src 'self' data:; style-src 'unsafe-inline'; script-src 'unsafe-inline' data:;";
+			metaTag.content = "default-src 'none'; font-src 'self' data:; img-src 'self' data:; style-src 'unsafe-inline'; media-src 'self' data:; script-src 'unsafe-inline' data:;";
 			this.doc.head.appendChild(metaTag);
 		}
 		if (this.options.insertMetaNoIndex) {