chore(deps): update dependency github-markdown-css to v5

Author: renovate-bot

package-lock.json

@@ -97,7 +97,7 @@
     "eslint-plugin-standard": "4.1.0",
     "esm": "3.2.25",
     "fs-extra": "10.0.0",
-    "github-markdown-css": "4.0.0",
+    "github-markdown-css": "5.0.0",
     "glob": "7.2.0",
     "gzip-size": "6.0.0",
     "highcharts": "9.3.0",