drop .net standard 1.6, not required as we target 1.4 already!

Author: Ivan Gavryliuk

src/Parquet/Parquet.csproj

@@ -1,6 +1,6 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFrameworks>netstandard1.4;netstandard1.6;net451</TargetFrameworks>
+    <TargetFrameworks>netstandard1.4;net451</TargetFrameworks>
     <Version>1.2.0.0</Version>
     <FileVersion>1.2.3.4</FileVersion>
     <AssemblyVersion>1.2.0.0</AssemblyVersion>
@@ -70,12 +70,6 @@ bug fixes:
   <PropertyGroup Condition="'$(Configuration)' == 'Release'">
     <GeneratePackageOnBuild>True</GeneratePackageOnBuild>
   </PropertyGroup>
-  <PropertyGroup Condition="'$(Configuration)|$(TargetFramework)|$(Platform)'=='Debug|netstandard1.6|AnyCPU'">
-    <DocumentationFile>bin\Debug\netstandard1.6\Parquet.xml</DocumentationFile>
-  </PropertyGroup>
-  <PropertyGroup Condition="'$(Configuration)|$(TargetFramework)|$(Platform)'=='Release|netstandard1.6|AnyCPU'">
-    <DocumentationFile>bin\Release\netstandard1.6\Parquet.xml</DocumentationFile>
-  </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(TargetFramework)|$(Platform)'=='Debug|netstandard1.4|AnyCPU'">
     <DocumentationFile>bin\Debug\netstandard1.4\Parquet.xml</DocumentationFile>
   </PropertyGroup>