[master] Update dependencies from dotnet/iot (#461)

* Update dependencies from https://github.com/dotnet/iot build 20190528.2

- Iot.Device.Bindings - 0.1.0-prerelease.19278.2
- System.Device.Gpio - 0.1.0-prerelease.19278.2

* Fix build break

eng/Version.Details.xml

 <?xml version="1.0" encoding="utf-8"?>
 <Dependencies>
   <ProductDependencies>
-    <Dependency Name="System.Device.Gpio" Version="0.1.0-prerelease.19274.1">
+    <Dependency Name="System.Device.Gpio" Version="0.1.0-prerelease.19278.2">
       <Uri>https://github.com/dotnet/iot</Uri>
-      <Sha>39558a2129638b2709e0647025334a5c8348f0b3</Sha>
+      <Sha>26e1b07557ce650d3110769262a27b50f38650be</Sha>
     </Dependency>
-    <Dependency Name="Iot.Device.Bindings" Version="0.1.0-prerelease.19274.1">
+    <Dependency Name="Iot.Device.Bindings" Version="0.1.0-prerelease.19278.2">
       <Uri>https://github.com/dotnet/iot</Uri>
-      <Sha>39558a2129638b2709e0647025334a5c8348f0b3</Sha>
+      <Sha>26e1b07557ce650d3110769262a27b50f38650be</Sha>
     </Dependency>
   </ProductDependencies>
   <ToolsetDependencies>

eng/Versions.props

@@ -2,7 +2,7 @@
 <Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <PropertyGroup>
     <PreReleaseVersionLabel>prerelease</PreReleaseVersionLabel>
-    <SystemDeviceGpioPackageVersion>0.1.0-prerelease.19274.1</SystemDeviceGpioPackageVersion>
-    <IotDeviceBindingsPackageVersion>0.1.0-prerelease.19274.1</IotDeviceBindingsPackageVersion>
+    <SystemDeviceGpioPackageVersion>0.1.0-prerelease.19278.2</SystemDeviceGpioPackageVersion>
+    <IotDeviceBindingsPackageVersion>0.1.0-prerelease.19278.2</IotDeviceBindingsPackageVersion>
   </PropertyGroup>
 </Project>

src/devices/Mcp23xxx/tests/Mcp23xxxTest.cs

@@ -99,6 +99,8 @@ namespace Iot.Device.Mcp23xxx.Tests
             public override void WriteByte(byte data) => throw new NotImplementedException();
 
             public override byte ReadByte() => throw new NotImplementedException();
+
+            public override void WriteRead(ReadOnlySpan<byte> writeBuffer, Span<byte> readBuffer) => throw new NotImplementedException();
         }
 
         /// <summary>

src/devices/Pcx857x/tests/Pcx857xTest.cs

@@ -62,6 +62,7 @@ namespace Iot.Device.Pcx857x.Tests
             // Don't need these
             public override void WriteByte(byte data) => DeviceMock.WriteByte(data);
             public override byte ReadByte() => DeviceMock.ReadByte();
+            public override void WriteRead(ReadOnlySpan<byte> writeBuffer, Span<byte> readBuffer) => throw new NotImplementedException();
         }
 
         /// <summary>