build: Addressed using ILMerge.exe from ILMerge nuget package, not

local copied files. The local copied ILMerge threw unkown exception as
below.
----------------------------------------------------------------------
An exception occurred during merging:
Unresolved assembly reference not allowed: System.Core.
   at System.Compiler.Ir2md.GetAssemblyRefIndex(AssemblyNode assembly)
   at System.Compiler.Ir2md.GetTypeRefIndex(TypeNode type)
   at System.Compiler.Ir2md.VisitReferencedType(TypeNode type)
   at System.Compiler.Ir2md.GetMemberRefIndex(Member m)
   at System.Compiler.Ir2md.GetMethodToken(Method m)
build: Incremented patch version,

to indicate that this fixes a bug.