[PATCH] Python 3.8 support

[Stephen Finucane]

On Thu, 2019-10-24 at 14:10 +1100, Andrew Donnellan wrote:
> Enable Python 3.8 in our tests and list it as a supported version.
> 
> Signed-off-by: Andrew Donnellan <ajd at linux.ibm.com>

LGTM, but let's hold off on this until 2.2 is out.

Stephen