Fix CI: Update Node.js version to 20.x for Docusaurus 3.x compatibility

Author: saiyam1814

.github/workflows/deploy.yml

@@ -17,7 +17,7 @@ jobs:
       - uses: actions/checkout@v4
       - uses: actions/setup-node@v4
         with:
-          node-version: '18.x'
+          node-version: '20.x'
           cache: 'npm'
 
       - name: Install dependencies

.github/workflows/node.js.yml

@@ -16,7 +16,7 @@ jobs:
 
     strategy:
       matrix:
-        node-version: [18.x, 20.x]
+        node-version: [20.x]
         # See supported Node.js release schedule at https://nodejs.org/en/about/releases/
 
     steps: