[DOCS] Changes hero image on the landing page and adds a line about l…

…icense. (#642) (#643)

Co-authored-by: István Zoltán Szabó <[email protected]>

.doc/index-custom-title-page.html

@@ -69,7 +69,7 @@ <h2>Documentation</h2>
       </p>
     </div>
     <div class="col-md-6 col-12">
-      <img class="w-100" src="https://images.contentstack.io/v3/assets/bltefdd0b53724fa2ce/blt0238da6059720d24/641dc21613a86c544af672ee/go-es-lp-hero.png" />
+      <img class="w-100" src="https://images.contentstack.io/v3/assets/bltefdd0b53724fa2ce/blt309b983fa254e216/642563bba793f910de28b9d1/ES_Go_landing_page.png" />
     </div>
   </div>
 
@@ -170,4 +170,5 @@ <h4 class="mt-3">
     </div>
   </div>
 
-  <p class="my-4"><a href="https://www.elastic.co/guide/index.html">View all Elastic docs</a></p>
+  <p class="my-4"><a href="https://www.elastic.co/guide/index.html">View all Elastic docs</a></p>
+  <p class="my-4"><small>The Go gopher available <a href="https://go.dev/blog/gopher">here</a> is created by Renee French and released under the Creative Commons <a href="https://creativecommons.org/licenses/by-sa/4.0/deed.en"> Attribution-Share Alike 4.0 International license</a>.</small></p>