adding dependencies

Author: AsabuHere

src/Twilio/Twilio.csproj

@@ -28,11 +28,10 @@
   <ItemGroup>
     <None Include="../../README.md" Pack="true" PackagePath="\"/>
   </ItemGroup>
-    <ItemGroup>
-    <Reference Include="System.Web.Extensions">
-      <HintPath>C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v3.5\System.Web.Extensions.dll</HintPath>
-    </Reference>
-    </ItemGroup>
+<ItemGroup>
+  <Reference Include="System.Web.Extensions">
+  </Reference>
+</ItemGroup>
   <ItemGroup>
     <Reference Include="System.Xml.Linq" />
     <PackageReference Include="Newtonsoft.Json" Version="13.0.1" />