Update supported Python versions.

 - (Removed) Python 2.7 was EOL on Jan 1st, 2020.
 - (Removed) Python 3.5 was EOL on Sep 13th, 2019.
 - Python 3.6 will end in 23 Dec 2021.
 - Python 3.7 will end in 27 Jun 2023.
 - (Adding) Python 3.8 released 14th Oct 2019.
 - (Adding) Python 3.9 released 05th Oct 2020.

Signed-off-by: Tim 'mithro' Ansell <me@mith.ro>

.travis.yml

diff --git a/.travis.yml b/.travis.yml
index 3bfc876..9f8b7fa 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,9 +1,10 @@
 language: python
 
 python:
-  - 3.5
   - 3.6
   - 3.7
+  - 3.8
+  - 3.9
 
 install:
   - source prepareenv.sh

tox.ini

diff --git a/tox.ini b/tox.ini
index 7320ce1..510194d 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,15 +1,15 @@
 [tox]
-envlist = py{27,34,35,36,37}
+envlist = py{35,36,37,38,39}
 
 [testenv]
 setenv =
     PYTHONPATH={toxinidir}/v2x
 basepython =
-    py27: python2.7
-    py34: python3.4
     py35: python3.5
     py36: python3.6
     py37: python3.7
+    py38: python3.8
+    py39: python3.9
 deps =
     check-manifest
     # If your project uses README.rst, uncomment the following: