udpate docusaurus and node versions

Author: bjuric

package.json

@@ -14,8 +14,8 @@
     "write-heading-ids": "docusaurus write-heading-ids"
   },
   "dependencies": {
-    "@docusaurus/core": "^2.0.0-beta.20",
-    "@docusaurus/preset-classic": "^2.0.0-beta.20",
+    "@docusaurus/core": "^2.0.0-beta.21",
+    "@docusaurus/preset-classic": "^2.0.0-beta.21",
     "@mdx-js/react": "^1.6.21",
     "@svgr/webpack": "^5.5.0",
     "clsx": "^1.1.1",

yarn.lock

@@ -2535,7 +2535,7 @@
     "@docsearch/css" "3.1.0"
     algoliasearch "^4.0.0"
 
-"@docusaurus/[email protected]", "@docusaurus/core@^2.0.0-beta.20":
+"@docusaurus/[email protected]", "@docusaurus/core@^2.0.0-beta.21":
   version "2.0.0-beta.21"
   resolved "https://registry.yarnpkg.com/@docusaurus/core/-/core-2.0.0-beta.21.tgz#50897317b22dbd94b1bf91bb30c2a0fddd15a806"
   integrity sha512-qysDMVp1M5UozK3u/qOxsEZsHF7jeBvJDS+5ItMPYmNKvMbNKeYZGA0g6S7F9hRDwjIlEbvo7BaX0UMDcmTAWA==
@@ -2763,7 +2763,7 @@
     sitemap "^7.1.1"
     tslib "^2.4.0"
 
-"@docusaurus/preset-classic@^2.0.0-beta.20":
+"@docusaurus/preset-classic@^2.0.0-beta.21":
   version "2.0.0-beta.21"
   resolved "https://registry.yarnpkg.com/@docusaurus/preset-classic/-/preset-classic-2.0.0-beta.21.tgz#1362d8650ebed22633db411caaba80075f7c86ce"
   integrity sha512-KvBnIUu7y69pNTJ9UhX6SdNlK6prR//J3L4rhN897tb8xx04xHHILlPXko2Il+C3Xzgh3OCgyvkoz9K6YlFTDw==