docs: Add github & issuess to top menu (#420)

Co-authored-by: Alvaro Saburido <alvaro.saburido@gmail.com>

docs/.vitepress/config.ts

@@ -110,6 +110,14 @@ export default defineConfig({
             text: 'Playground',
             link: 'https://playground.tresjs.org/',
           },
+          {
+            text: 'Github',
+            link: 'https://github.com/Tresjs/tres/',
+          },
+          {
+            text: 'Issues',
+            link: 'https://github.com/Tresjs/tres/issues',
+          },
           {
             text: 'Ecosystem',
             items: [