docs: add v2 docs links (TanStack#1676)

* docs: add v2 docs links

* revert (partial): docs: add v2 docs links

This partially reverts commit 48c40e3 - reverting docs Nav only.

* docs: add v2 docs link to home page banner.

Author: babycourageous

README.md

@@ -28,6 +28,7 @@ Enjoy this library? Try the entire [TanStack](https://tanstack.com)! [React Tabl
 
 ## Visit [react-query.tanstack.com](https://react-query.tanstack.com) for docs, guides, API and more!
 
+Still on **React Query v2**? No problem! Check out the v2 docs here: https://react-query-v2.tanstack.com/.
 ## Quick Features
 
 - Transport/protocol/backend agnostic data fetching (REST, GraphQL, promises, whatever!)

docs/src/pages/index.js

@@ -85,6 +85,17 @@ const Home = ({ sponsors }) => {
                       </a>
                     </div>
                   </div>
+                  <div className="mt-5">
+                    <p>
+                      Still using v2? No problem!{' '}
+                      <a
+                        href="https://react-query-v2.tanstack.com/docs/overview"
+                        className="text-blue-600 font-semibold transition-colors duration-150 ease-out"
+                      >
+                        Find the v2 docs here.
+                      </a>
+                    </p>
+                  </div>
                 </div>
               </div>
             </div>