Update project to new csproj format

Author: rasmusjp

Our.Umbraco.GraphQL.sln

@@ -9,7 +9,7 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Website", "samples\Website\
 EndProject
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "src", "src", "{BE019E17-BF39-443C-8D62-74940D3B6560}"
 EndProject
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Our.Umbraco.GraphQL", "src\Our.Umbraco.GraphQL\Our.Umbraco.GraphQL.csproj", "{59294783-3A17-479B-90C5-A3A2967176DE}"
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Our.Umbraco.GraphQL", "src\Our.Umbraco.GraphQL\Our.Umbraco.GraphQL.csproj", "{59294783-3A17-479B-90C5-A3A2967176DE}"
 EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution