Update assembly info file for v1.0.5-preview026

[version update]

Author: nfbot

source/nanoFramework.CoreLibrary/System/AssemblyInfo2.cs

@@ -15,4 +15,4 @@
 
 [assembly: AssemblyVersion("1.0.5.0")]
 [assembly: AssemblyFileVersion("1.0.5.0")]
-[assembly: AssemblyInformationalVersion("1.0.5-preview023")]
+[assembly: AssemblyInformationalVersion("1.0.5-preview026")]