Add embedded icon to NuGet package (resolve warning NU5048: The 'PackageIconUrl'/'iconUrl' element is deprecated)

Author: augustoproiete

assets/serilog-sink-nuget.png

@@ -10,7 +10,8 @@
     <SignAssembly>true</SignAssembly>
     <PublicSign Condition=" '$(OS)' != 'Windows_NT' ">true</PublicSign>
     <PackageTags>serilog;file</PackageTags>
-    <PackageIconUrl>http://serilog.net/images/serilog-sink-nuget.png</PackageIconUrl>
+    <PackageIcon>images\icon.png</PackageIcon>
+    <PackageIconUrl>https://serilog.net/images/serilog-sink-nuget.png</PackageIconUrl>
     <PackageProjectUrl>http://serilog.net</PackageProjectUrl>
     <PackageLicenseExpression>Apache-2.0</PackageLicenseExpression>
     <RepositoryUrl>https://github.com/serilog/serilog-sinks-file</RepositoryUrl>
@@ -56,4 +57,9 @@
     <PackageReference Include="System.Text.Encoding.Extensions" Version="4.3.0" />
     <PackageReference Include="System.Threading.Timer" Version="4.3.0" />
   </ItemGroup>
+
+  <ItemGroup>
+    <None Include="..\..\assets\serilog-sink-nuget.png" Pack="true" Visible="false" PackagePath="images\icon.png" />
+  </ItemGroup>
+
 </Project>