docs: add course banner

Author: tannerlinsley

docs/src/pages/index.js

@@ -71,6 +71,26 @@ const Home = props => {
             </div>
           </div>
         </div>
+        <div className="border-t-4 border-white shadow bg-coral text-white">
+          <div className="py-20">
+            <div className="mx-auto container text-center">
+              <div className="text-xl">ANNOUNCING</div>
+              <div className="text-3xl md:text-5xl font-bold">
+                React Query Essentials
+              </div>
+              <div className="text-xl italic">
+                The <strong>OFFICIAL</strong> React Query course by{' '}
+                <strong>Tanner Linsley</strong>
+              </div>
+              <a
+                href="https://learn.tanstack.com"
+                className="inline-block mt-8 rounded shadow-lg bg-white text-red-700 font-bold text-xl px-4 py-3"
+              >
+                ENROLL NOW
+              </a>
+            </div>
+          </div>
+        </div>
         <div className="text-lg border-t border-gray-200 bg-gray-50 ">
           <div className="py-24  ">
             <div className="mx-auto container">