Move winforms sample to use latest WebView2 prerelease SDK 0.9.579

Author: peiche-ms

SampleApps/WebView2WindowsFormsBrowser/WebView2WindowsFormsBrowser.csproj

@@ -9,6 +9,6 @@
     <ApplicationManifest>app.manifest</ApplicationManifest>
   </PropertyGroup>
   <ItemGroup>
-    <PackageReference Include="Microsoft.Web.WebView2" Version="0.9.538-prerelease" />
+    <PackageReference Include="Microsoft.Web.WebView2" Version="0.9.579-prerelease" />
   </ItemGroup>
 </Project>