fix doco link

Author: SimonCropp

Directory.Build.props

@@ -10,7 +10,7 @@
     <Copyright>Copyright $([System.DateTime]::UtcNow.ToString(yyyy)). All rights reserved</Copyright>
     <PackageTags>NServiceBus, ProtoBuf</PackageTags>
     <PackageIconUrl>https://raw.githubusercontent.com/NServiceBusExtensions/NServiceBus.ProtoBufNet/master/icon.png</PackageIconUrl>
-    <PackageProjectUrl>https://docs.particular.net/nuget/NServiceBus.ProtoBufNet</PackageProjectUrl>
+    <PackageProjectUrl>https://docs.particular.net/nuget/NServiceBus.ProtoBuf</PackageProjectUrl>
     <RepositoryUrl>https://github.com/NServiceBusExtensions/NServiceBus.ProtoBufNet</RepositoryUrl>
     <PackageOutputPath>..\nugets</PackageOutputPath>
     <SignAssembly>true</SignAssembly>