Update dependency @next/mdx to v12

package.json

@@ -22,7 +22,7 @@
     "@fabric-ds/react": "^1.0.4",
     "@jsdevtools/rehype-toc": "^3.0.2",
     "@mdx-js/loader": "^1.6.22",
-    "@next/mdx": "^11.1.2",
+    "@next/mdx": "^12.0.0",
     "@sindresorhus/slugify": "^1.1.0",
     "autoprefixer": "^10.1.0",
     "decamelize": "^5.0.0",

yarn.lock

@@ -314,10 +314,10 @@
   resolved "https://registry.yarnpkg.com/@next/env/-/env-12.1.0.tgz#73713399399b34aa5a01771fb73272b55b22c314"
   integrity sha512-nrIgY6t17FQ9xxwH3jj0a6EOiQ/WDHUos35Hghtr+SWN/ntHIQ7UpuvSi0vaLzZVHQWaDupKI+liO5vANcDeTQ==
 
-"@next/mdx@^11.1.2":
-  version "11.1.2"
-  resolved "https://registry.yarnpkg.com/@next/mdx/-/mdx-11.1.2.tgz#cf4fbbc453d827008e82daa97591755e1321c29f"
-  integrity sha512-uRodX0OGSWMGTzun1QGfpXisKjz4ptWoizYqhXWZubLFJsRG/GKbB9n9hh3l48KlzKMO2S1REAOKJd+x9h/nWw==
+"@next/mdx@^12.0.0":
+  version "12.1.4"
+  resolved "https://registry.yarnpkg.com/@next/mdx/-/mdx-12.1.4.tgz#06a73b9d97b2a26c17e2f9e11974a7138e53d1a6"
+  integrity sha512-AECT8+2j9bhjiF5WIA8xIfBF5Otf5uUFydIP3tf53qz+PNzlhnQvMd1zLsAIZ7+Wvj4WgnPes1Lxl8CHri20WQ==
 
 "@next/[email protected]":
   version "12.1.0"