Build: explicitly require dotnet sdk version

global.json

@@ -0,0 +1,5 @@
+{
+    "sdk": {
+      "version": "2.1.3"
+    }
+}

paket.dependencies

@@ -1,6 +1,6 @@
 source https://www.nuget.org/api/v2
 
-nuget FSharp.Core
+nuget FSharp.Core 4.2.3
 nuget FSharp.Compiler.Tools
 
 nuget NUnit ~> 3.0 framework:net45,netcoreapp1.1,netcoreapp2.0
@@ -50,7 +50,7 @@ nuget runtime.win-x86.Microsoft.NETCore.DotNetAppHost framework:net45,netcoreapp
 group Build
     source https://www.nuget.org/api/v2
     nuget FAKE ~> 4.1
-    nuget NUnit.ConsoleRunner ~> 3.0
+    nuget NUnit.ConsoleRunner
     nuget FSharp.Formatting !~> 2.4
     nuget NuGet.CommandLine
 

src/UnitTests/UnitTests.csproj.paket.references

@@ -1,13 +1,13 @@
 NUnit
 NUnitLite content:none
-System.Reflection framework:netcoreapp1.1
-System.Reflection.Extensions framework:netcoreapp1.1
-System.Reflection.TypeExtensions framework:netcoreapp1.1
-System.Threading.Tasks.Parallel framework:netcoreapp1.1
-System.Xml.XmlSerializer framework:netcoreapp1.1
-System.Runtime framework:netcoreapp1.1
-System.Runtime.Numerics framework:netcoreapp1.1
-System.Runtime.Serialization.Xml framework:netcoreapp1.1
-System.Runtime.Serialization.Primitives framework:netcoreapp1.1
-System.Runtime.Serialization.Formatters framework:netcoreapp1.1
-System.Security.Cryptography.Algorithms framework:netcoreapp1.1
+System.Reflection framework:netcoreapp1.1,netcoreapp2.0
+System.Reflection.Extensions framework:netcoreapp1.1,netcoreapp2.0
+System.Reflection.TypeExtensions framework:netcoreapp1.1,netcoreapp2.0
+System.Threading.Tasks.Parallel framework:netcoreapp1.1,netcoreapp2.0
+System.Xml.XmlSerializer framework:netcoreapp1.1,netcoreapp2.0
+System.Runtime framework:netcoreapp1.1,netcoreapp2.0
+System.Runtime.Numerics framework:netcoreapp1.1,netcoreapp2.0
+System.Runtime.Serialization.Xml framework:netcoreapp1.1,netcoreapp2.0
+System.Runtime.Serialization.Primitives framework:netcoreapp1.1,netcoreapp2.0
+System.Runtime.Serialization.Formatters framework:netcoreapp1.1,netcoreapp2.0
+System.Security.Cryptography.Algorithms framework:netcoreapp1.1,netcoreapp2.0