Merge pull request #5 from eiriktsarpalis/multi-target

Add multi-target support; Lower FSharp.Core version

Author: alfonsogarciacaro

src/UnitsOfMeasure.Extra.fsproj

@@ -3,7 +3,7 @@
   <PropertyGroup>
     <Version>1.0.0</Version>
     <PackageVersion>1.0.0-beta-004</PackageVersion>
-    <TargetFramework>netstandard2.0</TargetFramework>
+    <TargetFrameworks>net45;netstandard2.0</TargetFrameworks>
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
   </PropertyGroup>
   <ItemGroup>
@@ -12,4 +12,7 @@
   <ItemGroup>
     <Content Include="*.fsproj; *.fs" PackagePath="fable\" />
   </ItemGroup>
+  <ItemGroup>
+    <PackageReference Update="FSharp.Core" Version="4.1.17" />
+  </ItemGroup>
 </Project>