fix: docusaurus/website/package.json & docusaurus/website/yarn.lock to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JS-IP-12704893
- https://snyk.io/vuln/SNYK-JS-IP-12761655

Author: snyk-bot

docusaurus/website/package.json

@@ -6,7 +6,7 @@
     "deploy": "docusaurus deploy"
   },
   "dependencies": {
-    "@docusaurus/core": "^2.0.0-alpha.30",
+    "@docusaurus/core": "^2.0.1",
     "@docusaurus/preset-classic": "^2.0.0-alpha.30",
     "classnames": "^2.2.6",
     "react": "^16.11.0",