Added missing reference to Angle.cs in Src/UnitsNet/UnitsNet.netcore45.csproj.

Author: angularsen

Src/UnitsNet/UnitsNet.netcore45.csproj

@@ -95,6 +95,7 @@
     <!-- A reference to the entire .Net Framework and Windows SDK are automatically included -->
   </ItemGroup>
   <ItemGroup>
+    <Compile Include="Angle.cs" />
     <Compile Include="Area.cs" />
     <Compile Include="ElectricPotential.cs" />
     <Compile Include="EnumUtils.cs" />