Bump version number to 2.0.0.
Bump version number to 2.0.0.

ksubramz/CppMicroServices,ksubramz/CppMicroServices,CppMicroServices/CppMicroServices,saschazelzer/CppMicroServices,mobileFX/CppMicroServices,ksubramz/CppMicroServices,quinnlin/CppMicroServices,CppMicroServices/CppMicroServices,CppMicroServices/CppMicroServices,mobileFX/CppMicroServices,ksubramz/CppMicroServices,quinnlin/CppMicroServices,CppMicroServices/CppMicroServices,Heather/CppMicroServices,saschazelzer/CppMicroServices,Heather/CppMicroServices,ksubramz/CppMicroServices,CppMicroServices/CppMicroServices