feat: update docusaurus

.gitlab-ci.yml

-image: node:14.17.1-slim
+image: node:16.14.2-slim
 
 stages:
   - 🧪 test

package.json

@@ -16,8 +16,8 @@
     "lint-fix": "eslint . --fix"
   },
   "dependencies": {
-    "@docusaurus/core": "2.0.0-beta.18",
-    "@docusaurus/preset-classic": "2.0.0-beta.18",
+    "@docusaurus/core": "2.0.0-beta.21",
+    "@docusaurus/preset-classic": "2.0.0-beta.21",
     "@fortawesome/fontawesome-svg-core": "^6.1.1",
     "@fortawesome/free-regular-svg-icons": "^6.1.1",
     "@fortawesome/free-solid-svg-icons": "^6.1.1",
@@ -52,6 +52,7 @@
     "eslint-config-prettier": "^8.3.0",
     "eslint-plugin-prettier": "^3.4.0",
     "eslint-plugin-react": "^7.24.0",
+    "node": "^16.14.2",
     "prettier": "^2.3.2"
   }
 }