Merge branch 'release/3.0.4' into develop

package.json

 {
     "name": "@iktakahiro/markdown-it-katex",
-    "version": "3.0.3",
+    "version": "3.0.4",
     "description": "Fast math support for markdown-it with KaTeX",
     "main": "index.js",
     "scripts": {