Increase Minimum Version of Visual Studio to 15.3.0

Antiforgery.sln

@@ -1,7 +1,7 @@
 Microsoft Visual Studio Solution File, Format Version 12.00
 # Visual Studio 15
 VisualStudioVersion = 15.0.26208.0
-MinimumVisualStudioVersion = 10.0.40219.1
+MinimumVisualStudioVersion = 15.0.26730.03
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "src", "src", "{71D070C4-B325-48F7-9F25-DD4E91C2BBCA}"
 EndProject
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "test", "test", "{6EDD8B57-4DE8-4246-A6A3-47ECD92740B4}"