version up: Cython 0.28.2, matplotlib 2.1.2

- not all SR was using Cython 0.28.2
- with an upcoming upgrade of pycocotools, matplotlib>=2.1.0 will be required
4 jobs for defaults
Status Job ID Name Coverage
  External
failed SlapOS.SlapRunner.ResilienceTest-Master

08:11:12

failed SlapOS.SoftwareReleases.IntegrationTest-Master.Python2

08:26:20

failed SlapOS.SoftwareReleases.IntegrationTest-Master.Python3

01:49:13

failed SlapOS.SoftwareReleases.IntegrationTest-Master.Python3