Update Signing.props

Author: SteveSandersonMS

eng/Signing.props

@@ -193,6 +193,9 @@
     <_MonoBinaryToExcludeFromSigning Include="System.Xml.XPath.XDocument.dll" />
     <_MonoBinaryToExcludeFromSigning Include="System.Xml.XPath.XmlDocument.dll" />
     <_MonoBinaryToExcludeFromSigning Include="System.Xml.Xsl.Primitives.dll" />
+    <_MonoBinaryToExcludeFromSigning Include="WebAssembly.Bindings.dll" />
+    <_MonoBinaryToExcludeFromSigning Include="WebAssembly.Net.Http.dll" />
+    <_MonoBinaryToExcludeFromSigning Include="WebAssembly.Net.WebSockets.dll" />
 
     <FileSignInfo Include="@(_MonoBinaryToExcludeFromSigning)" CertificateName="None" />
     <SignValidationExclusionList Include="@(_MonoBinaryToExcludeFromSigning)" />