website/package.json: bump node_modules and update yarn.lock

bump react, react-dom, docusaurus, classnames and dependencies (yarn.lock)

Signed-off-by: leonnicolas <leonloechner@gmx.de>

website/package.json

@@ -9,11 +9,11 @@
     "deploy": "docusaurus deploy"
   },
   "dependencies": {
-    "@docusaurus/core": "2.0.0-alpha.71",
-    "@docusaurus/preset-classic": "2.0.0-alpha.71",
-    "classnames": "^2.2.6",
-    "react": "^16.8.4",
-    "react-dom": "^16.8.4"
+    "@docusaurus/core": "^2.0.0-beta.0",
+    "@docusaurus/preset-classic": "^2.0.0-beta.0",
+    "classnames": "^2.3.1",
+    "react": "^17.0.2",
+    "react-dom": "^17.0.2"
   },
   "browserslist": {
     "production": [