Updating template to use the latest version of the extensions metadata generator

Author: fabiocav

src/Azure.Functions.Cli/StaticResources/ExtensionsProj.csproj.template

@@ -5,6 +5,6 @@
 	<DefaultItemExcludes>**</DefaultItemExcludes>
   </PropertyGroup>
   <ItemGroup>
-    <PackageReference Include="Microsoft.Azure.WebJobs.Script.ExtensionsMetadataGenerator" Version="1.0.0-beta2" />
+    <PackageReference Include="Microsoft.Azure.WebJobs.Script.ExtensionsMetadataGenerator" Version="1.0.0-beta3" />
   </ItemGroup>
 </Project>