(GH-208) Bump dotnet version of match AppVeyor

We should handle the execution of the tests in the cake script as part
of a later scope of work.

Author: gep13

src/MagicChunks.Tests/MagicChunks.Tests.csproj

@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <TargetFramework>netcoreapp2.0</TargetFramework>
-    <RuntimeFrameworkVersion>2.0.3</RuntimeFrameworkVersion>
+    <RuntimeFrameworkVersion>2.0.9</RuntimeFrameworkVersion>
     <Authors>Sergey Zwezdin</Authors>
     <Company />
     <Product>Magic Chunks</Product>