Run tests under Python 3.8 on Travis.
Run tests under Python 3.8 on Travis.

andrewsomething/libcloud,andrewsomething/libcloud,mistio/libcloud,Kami/libcloud,andrewsomething/libcloud,apache/libcloud,mistio/libcloud,apache/libcloud,apache/libcloud,mistio/libcloud,Kami/libcloud,Kami/libcloud