lowered the .NET Standard version of the project

Author: tsutomi

src/Deveel.Workflows/Deveel.Workflows.csproj

@@ -4,7 +4,7 @@
     <Description>A lightweight library for designing and executing workflows through .NET</Description>
     <Copyright>2017 Deveel</Copyright>
     <Authors>Antonello Provenzano</Authors>
-    <TargetFramework>netstandard1.6</TargetFramework>
+    <TargetFramework>netstandard1.5</TargetFramework>
     <AssemblyName>Deveel.Workflows</AssemblyName>
     <PackageId>Deveel.Workflows</PackageId>
     <PackageTags>workflow;dotnet;core;activity;activities;job;graph</PackageTags>

test/Deveel.Workflows.Tests/Deveel.Workflows.Tests.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>netcoreapp1.0</TargetFramework>
+    <TargetFramework>netcoreapp1.1</TargetFramework>
     <AssemblyName>Deveel.Workflows.Tests</AssemblyName>
     <PackageId>Deveel.Workflows.Tests</PackageId>
     <GenerateRuntimeConfigurationFiles>true</GenerateRuntimeConfigurationFiles>