Update download links to point to releases

Author: ViralBShah

docs/index.html

@@ -20,8 +20,7 @@ <h1 class="header">OpenLibm</h1>
         <p class="header">A high quality system independent, portable, open source libm implementation</p>
 
         <ul>
-          <li class="download"><a class="buttons" href="https://github.com/JuliaLang/openlibm/archive/v0.4.1.zip">Download ZIP</a></li>
-          <li class="download"><a class="buttons" href="https://github.com/JuliaLang/openlibm/archive/v0.4.1.tar.gz">Download TAR</a></li>
+          <li class="download"><a class="buttons" href="https://github.com/JuliaMath/openlibm/releases">Download</a></li>
           <li><a class="buttons github" href="https://github.com/JuliaLang/openlibm">View On GitHub</a></li>
         </ul>