Improve visibility of supported frameworks in nuspec

Fixes #206

Author: const-cloudinary

CloudinaryDotNet.nuspec

@@ -15,14 +15,18 @@
     <copyright>Copyright 2017</copyright>
     <tags>Image Video Responsive Web Utility CDN Performance Resize Crop Rotate Quality Watermark Gif Jpg Jpeg Bitmap PNG Tiff Webp Webm mp4 avi Filter Effect</tags>
     <dependencies>
-     <group>
-         <dependency id="Newtonsoft.Json" version="12.0.1" />
-     </group>
+      <group>
+        <dependency id="Newtonsoft.Json" version="12.0.1" />
+      </group>
       <group targetFramework="net45">
-         <dependency id="System.Runtime.InteropServices.RuntimeInformation" version="4.3.0" />
-         <dependency id="System.Globalization" version="4.3.0" />
-         <dependency id="System.Text.Encodings.Web" version="4.5.0" />
+        <dependency id="System.Runtime.InteropServices.RuntimeInformation" version="4.3.0" />
+        <dependency id="System.Globalization" version="4.3.0" />
+        <dependency id="System.Text.Encodings.Web" version="4.5.0" />
+      </group>
+      <group targetFramework="netstandard1.3">
       </group>
+      <group targetFramework="netstandard2.0">
+      </group>    
     </dependencies>
   </metadata>
   <files>