Fix appveyor link and badge to master branch

README.md

@@ -1,8 +1,8 @@
 
 <h1>
     <img src="https://i.imgur.com/G6Mleco.png"> Ryujinx
-    <a href="https://ci.appveyor.com/project/gdkchan/ryujinx" target="_blank">
-        <img src="https://ci.appveyor.com/api/projects/status/ssg4jwu6ve3k594s?svg=true">
+    <a href="https://ci.appveyor.com/project/gdkchan/ryujinx?branch=master" target="_blank">
+        <img src="https://ci.appveyor.com/api/projects/status/ssg4jwu6ve3k594s/branch/master?svg=true">
     </a>
     <a href="https://discord.gg/N2FmfVc">
         <img src="https://img.shields.io/discord/410208534861447168.svg">