Fix: Update markdown-to-jsx to 5.3.0 (#416)

Author: n1313

package.json

@@ -59,7 +59,7 @@
     "listify": "^1.0.0",
     "loader-utils": "^1.1.0",
     "lodash": "^4.17.4",
-    "markdown-to-jsx": "5.2.0",
+    "markdown-to-jsx": "^5.3.0",
     "minimist": "^1.2.0",
     "pretty-format": "^19.0.0",
     "prop-types": "^15.5.8",