[atkmm] NMake Makefiles: Bump glibmm version

[Chun-wei Fan <fanchunwei src gnome org>]

commit aba60e795be87c8dfdcecb45253e03786d6019d5
Author: Chun-wei Fan <fanchunwei src gnome org>
Date:   Fri Feb 7 19:10:14 2020 +0800

    NMake Makefiles: Bump glibmm version
    
    glibmm master is now versioned at 2.64, so update this accordingly

 MSVC_NMake/config-msvc.mak | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/MSVC_NMake/config-msvc.mak b/MSVC_NMake/config-msvc.mak
index 2100c37..db911fb 100644
--- a/MSVC_NMake/config-msvc.mak
+++ b/MSVC_NMake/config-msvc.mak
@@ -13,7 +13,7 @@ GLIB_API_VERSION = 2.0
 LIBSIGC_MAJOR_VERSION = 3
 LIBSIGC_MINOR_VERSION = 0
 GLIBMM_MAJOR_VERSION = 2
-GLIBMM_MINOR_VERSION = 62
+GLIBMM_MINOR_VERSION = 64
 
 
 !if "$(CFG)" == "debug" || "$(CFG)" == "Debug"