Update dependencies from https://github.com/dotnet/iot build 20190606.3 (#481)

- Iot.Device.Bindings - 0.1.0-prerelease.19306.3
- System.Device.Gpio - 0.1.0-prerelease.19306.3

eng/Version.Details.xml

 <?xml version="1.0" encoding="utf-8"?>
 <Dependencies>
   <ProductDependencies>
-    <Dependency Name="System.Device.Gpio" Version="0.1.0-prerelease.19305.1">
+    <Dependency Name="System.Device.Gpio" Version="0.1.0-prerelease.19306.3">
       <Uri>https://github.com/dotnet/iot</Uri>
-      <Sha>4c32a9d7532ad790926cabcabef760e1560f3730</Sha>
+      <Sha>8f0a4a533867417844e72d045d66c1eb0e734ebc</Sha>
     </Dependency>
-    <Dependency Name="Iot.Device.Bindings" Version="0.1.0-prerelease.19305.1">
+    <Dependency Name="Iot.Device.Bindings" Version="0.1.0-prerelease.19306.3">
       <Uri>https://github.com/dotnet/iot</Uri>
-      <Sha>4c32a9d7532ad790926cabcabef760e1560f3730</Sha>
+      <Sha>8f0a4a533867417844e72d045d66c1eb0e734ebc</Sha>
     </Dependency>
   </ProductDependencies>
   <ToolsetDependencies>

eng/Versions.props

@@ -2,8 +2,11 @@
 <Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <PropertyGroup>
     <PreReleaseVersionLabel>prerelease</PreReleaseVersionLabel>
-    <SystemDeviceGpioPackageVersion>0.1.0-prerelease.19305.1</SystemDeviceGpioPackageVersion>
-    <IotDeviceBindingsPackageVersion>0.1.0-prerelease.19305.1</IotDeviceBindingsPackageVersion>
+    <!-- dotnet/iot dependencies -->
+    <SystemDeviceGpioPackageVersion>0.1.0-prerelease.19306.3</SystemDeviceGpioPackageVersion>
+    <IotDeviceBindingsPackageVersion>0.1.0-prerelease.19306.3</IotDeviceBindingsPackageVersion>
+
+    <!-- dotnet/arcade dependencies -->
     <MicrosoftDotNetGenAPIPackageVersion>1.0.0-beta.19306.12</MicrosoftDotNetGenAPIPackageVersion>
   </PropertyGroup>
 </Project>