Use py3 as the default runtime for tox

Moving on py3 as the default runtime for tox to avoid to update this at
each new cycle.

Wallaby support officially the following runtimes [1]:
- Python 3.6
- Python 3.8

During Victoria Python 3.7 was used as the default runtime [2] however this
version isn't longer officially supported.

[1] https://governance.openstack.org/tc/reference/runtimes/wallaby.html#python-runtimes-for-wallaby
[2] https://governance.openstack.org/tc/reference/runtimes/victoria.html#python-runtimes-for-victoria

Change-Id: I4bad27f2daab336437ae7a85c79a4928b9fe894c

1 files changed, 1 insertions, 1 deletions

diff --git a/tox.ini b/tox.ini
index 2b3dd76..d5b6190 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,6 +1,6 @@
 [tox]
 minversion = 3.1
-envlist = py36,py38,pep8
+envlist = py36,py3,pep8
 ignore_basepython_conflict = true
 
 [testenv]