Updated nuspec - added dependency on Polly

Author: dylan-asos

nuspec/Sendgrid.9.5.0.nuspec

@@ -20,11 +20,13 @@
             <group targetFramework=".NETFramework4.0">
                 <dependency id="Newtonsoft.Json" version="9.0.1" />
                 <dependency id="System.Net.Http" version="4.0.0" />
+                <dependency id="Polly" version="5.2.0" />
             </group>
             <group targetFramework=".NETStandard1.3">
                 <dependency id="NETStandard.Library" version="1.6.1" />
                 <dependency id="Newtonsoft.Json" version="9.0.1" />
                 <dependency id="Microsoft.AspNetCore.Http.Abstractions" version="1.1.0" />
+                <dependency id="Polly" version="5.2.0" />
             </group>
         </dependencies>
     </metadata>