chore: pin docs dependencies

Author: prevwong

site/package.json

@@ -9,13 +9,13 @@
     "deploy": "docusaurus deploy"
   },
   "dependencies": {
-    "@docusaurus/core": "^2.0.0-beta.0",
-    "@docusaurus/plugin-client-redirects": "^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",
-    "semver": "^7.3.5"
+    "@docusaurus/core": "2.0.0-beta.0",
+    "@docusaurus/plugin-client-redirects": "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",
+    "semver": "7.3.5"
   },
   "browserslist": {
     "production": [