Update MailKit to 4.16.0 (#134)

Author: stidsborg

Samples/Sample.ConsoleApp/Sample.ConsoleApp.csproj

@@ -15,7 +15,7 @@
     </ItemGroup>
 
     <ItemGroup>
-      <PackageReference Include="MailKit" Version="4.15.1" />
+      <PackageReference Include="MailKit" Version="4.16.0" />
       <PackageReference Include="Serilog" Version="4.3.1" />
     </ItemGroup>