Bump highlight.js from 9.17.1 to 10.4.1 in /book/6-end

Bumps [highlight.js](https://github.com/highlightjs/highlight.js) from 9.17.1 to 10.4.1.
- [Release notes](https://github.com/highlightjs/highlight.js/releases)
- [Changelog](https://github.com/highlightjs/highlight.js/blob/master/CHANGES.md)
- [Commits](highlightjs/highlight.js@9.17.1...10.4.1)

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

Author: dependabot[bot]

book/6-end/package.json

@@ -25,7 +25,7 @@
     "front-matter": "4.0.2",
     "handlebars": "4.7.6",
     "he": "1.2.0",
-    "highlight.js": "10.1.2",
+    "highlight.js": "10.4.1",
     "isomorphic-unfetch": "^3.0.0",
     "lodash": "4.17.20",
     "marked": "1.1.1",

book/6-end/yarn.lock

@@ -4729,10 +4729,10 @@ he@1.2.0:
   resolved "https://registry.yarnpkg.com/he/-/he-1.2.0.tgz#84ae65fa7eafb165fddb61566ae14baf05664f0f"
   integrity sha512-F/1DnUGPopORZi0ni+CvrCgHQ5FyEAHRLSApuYWMmrbSwoN2Mn/7k+Gl38gJnR7yyDZk6WLXwiGod1JOWNDKGw==
 
-highlight.js@10.1.2:
-  version "10.1.2"
-  resolved "https://registry.yarnpkg.com/highlight.js/-/highlight.js-10.1.2.tgz#c20db951ba1c22c055010648dfffd7b2a968e00c"
-  integrity sha512-Q39v/Mn5mfBlMff9r+zzA+gWxRsCRKwEMvYTiisLr/XUiFI/4puWt0Ojdko3R3JCNWGdOWaA5g/Yxqa23kC5AA==
+highlight.js@10.4.1:
+  version "10.4.1"
+  resolved "https://registry.yarnpkg.com/highlight.js/-/highlight.js-10.4.1.tgz#d48fbcf4a9971c4361b3f95f302747afe19dbad0"
+  integrity sha512-yR5lWvNz7c85OhVAEAeFhVCc/GV4C30Fjzc/rCP0aCWzc1UUOPUk55dK/qdwTZHBvMZo+eZ2jpk62ndX/xMFlg==
 
 hmac-drbg@^1.0.0:
   version "1.0.1"