bump mermaid version to support state diagrams

Author: nam

package.json

@@ -95,7 +95,7 @@
     "markdown-it-sup": "^1.0.0",
     "markdown-toc": "^1.2.0",
     "mdurl": "^1.0.1",
-    "mermaid": "^8.0.0-rc.8",
+    "mermaid": "^8.4.2",
     "moment": "^2.10.3",
     "mousetrap": "^1.6.2",
     "mousetrap-global-bind": "^1.1.0",