#315 Update .NET standard from version 1.2 to version 2.0

src/Mollie.Api/Mollie.Api.csproj

@@ -1,7 +1,6 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>netstandard1.2;net45</TargetFrameworks>
     <Version>2.3.0.2</Version>
     <GeneratePackageOnBuild>True</GeneratePackageOnBuild>
     <Authors>Vincent Kok</Authors>
@@ -14,29 +13,12 @@
     <FileVersion>2.3.0.2</FileVersion>
     <PackageLicenseUrl>https://github.com/Viincenttt/MollieApi/blob/development/LICENSE</PackageLicenseUrl>
     <PackageVersion>2.3.0.2</PackageVersion>
+    <TargetFramework>netstandard2.0</TargetFramework>
   </PropertyGroup>
 
-  <ItemGroup Condition="'$(TargetFramework)' == 'net45'">
-    <Reference Include="System.Net.Http" />
-  </ItemGroup>
-
-  <ItemGroup Condition="'$(TargetFramework)' == 'netstandard1.2'">
-    <Reference Include="System.Net.Http" />
-  </ItemGroup>
-
   <ItemGroup>
     <PackageReference Include="Newtonsoft.Json" Version="12.0.1" />
-  </ItemGroup>
-
-  <ItemGroup>
-    <Reference Include="Newtonsoft.Json">
-      <HintPath>..\packages\Newtonsoft.Json.11.0.2\lib\net45\Newtonsoft.Json.dll</HintPath>
-    </Reference>
-    <Reference Include="System.Net.Http" />
-  </ItemGroup>
-
-  <ItemGroup>
-    <PackageReference Update="NETStandard.Library" Version="1.6.1" />
+    <PackageReference Include="System.Runtime.Serialization.Primitives" Version="4.3.0" />    
   </ItemGroup>
 
   <ItemGroup>