Upgrade corefx packages to 4.4.0

Author: Nate McMaster

build/dependencies.props

@@ -1,7 +1,7 @@
 <Project>
   <PropertyGroup>
     <AspNetCoreVersion>2.0.0-*</AspNetCoreVersion>
-    <CoreFxVersion>4.3.0</CoreFxVersion>
+    <CoreFxVersion>4.4.0-*</CoreFxVersion>
     <InternalAspNetCoreSdkVersion>2.1.0-*</InternalAspNetCoreSdkVersion>
     <NETStandardImplicitPackageVersion>$(BundledNETStandardPackageVersion)</NETStandardImplicitPackageVersion>
     <NETStandardLibraryNETFrameworkVersion>2.0.0-*</NETStandardLibraryNETFrameworkVersion>