chore: beautify footer: github -> GitHub (#5220)

apollo-portal/src/main/resources/static/views/common/footer.html

@@ -20,7 +20,7 @@
         Copyright 2024 Apollo Authors
         <a class="footer-repo" href="https://github.com/apolloconfig/apollo" target="_blank">
             <img class="footer-repo-img" src="{{ '/img/github-fill.svg' | prefixPath }}">
-            <span class="footer-repo-name">github</span>
+            <span class="footer-repo-name">GitHub</span>
         </a>
     </p>
 </div>