chore(package): update core-js to version 2.0.2
chore(package): update core-js to version 2.0.2

http://greenkeeper.io/
karma-runner/karma,panrafal/karma,SamuelMarks/karma,wesleycho/karma,maksimr/karma,ernsheong/karma,kahwee/karma,SamuelMarks/karma,karma-runner/karma,david-garcia-nete/karma,johnjbarton/karma,karma-runner/karma,wesleycho/karma,mprobst/karma,johnjbarton/karma,panrafal/karma,karma-runner/karma,maksimr/karma,ernsheong/karma,johnjbarton/karma,johnjbarton/karma,pedrotcaraujo/karma,kahwee/karma,shirish87/karma,david-garcia-nete/karma,shirish87/karma,kahwee/karma,Dignifiedquire/karma,Dignifiedquire/karma,mprobst/karma,Dignifiedquire/karma,ernsheong/karma,kahwee/karma,SamuelMarks/karma,wesleycho/karma,shirish87/karma,mprobst/karma,david-garcia-nete/karma,pedrotcaraujo/karma,maksimr/karma,pedrotcaraujo/karma,panrafal/karma,Dignifiedquire/karma,wesleycho/karma,pedrotcaraujo/karma