Add KVER=5.2 and KVER=5.3 to travis configuration

[bentolor]

Include Kernel 5.2 and 5.3 into Travic Configuration.

I only started this, because there is no working anbox-modules-dkms for Debian/Ubuntu and I wanted to fix that. After my first preparations I realized that it is already fixed in master but not uploaded into the PPA http://ppa.launchpad.net/morphis/anbox-support/ubuntu

@morphis What can we do to assist you in getting a fresh anbox-modules-dkms within the PPA? Ideally also for eoan

Related to #37 #28
Solved in #19

[morphis]

LGTM

For the PPA see my answer on anbox/anbox#1273

[bentolor]

So if I understand you correctly: With Kernel 5.0+ you would no longer need any DKMS as soon as anbox starts to use the kernel-provided facility.

Until this is fixed, we still need this DKMS.

Therefore the goal is to use the new Kernel infrastructure and not to provide a PPA update for Ubuntu eoan and newer. I think this is reasonable, but should probably be fixed until Ubuntu 20.04 LTS Focal fossa