Remove 3.4 (EOL)

See https://pythoninsider.blogspot.com/2019/03/python-3410-is-now-available.html

> Python 3.4.10 is the final release in the Python 3.4 series.  As of this release, the 3.4 branch has been retired, no further changes to 3.4 will be accepted, and no new releases will be made.  This is standard Python policy; Python releases get five years of support and are then retired.

Author: tianon

.travis.yml

@@ -50,20 +50,6 @@ matrix:
       env: VERSION=3.5 VARIANT=alpine3.9
     - os: linux
       env: VERSION=3.5 VARIANT=alpine3.8
-    - os: linux
-      env: VERSION=3.4 VARIANT=stretch
-    - os: linux
-      env: VERSION=3.4 VARIANT=stretch/slim
-    - os: linux
-      env: VERSION=3.4 VARIANT=jessie
-    - os: linux
-      env: VERSION=3.4 VARIANT=jessie/slim
-    - os: linux
-      env: VERSION=3.4 VARIANT=wheezy
-    - os: linux
-      env: VERSION=3.4 VARIANT=alpine3.9
-    - os: linux
-      env: VERSION=3.4 VARIANT=alpine3.8
     - os: windows
       dist: 1803-containers
       env: VERSION=2.7 VARIANT=windows/windowsservercore-1803