* update develop whl package name

* distingush cpu and gpu name

* fix ref_gcc

* change whl name

* upgrade gcc 4.8 to 5.4 in ubuntu_dev

* update gcc4.8 to 5.4 in centos

* Upgrade pip from 18.0 to 20.0.1

* change 2.1.0_dev0 to 2.1.0.dev0 in gpu version