Python 3.8 on Xenial Linux

Author: shmilylty

.travis.yml

@@ -12,6 +12,9 @@ matrix:
     - name: "Python 3.7 on Xenial Linux"
       python: 3.7           # this works for Linux but is ignored on macOS or Windows
       dist: xenial          # required for Python >= 3.7
+    - name: "Python 3.8 on Xenial Linux"
+      python: 3.8-dev           # this works for Linux but is ignored on macOS or Windows
+      dist: xenial          # required for Python >= 3.7
     - name: "Python 3.7 on macOS"
       os: osx
       osx_image: xcode10.2  # Python 3.7 running on macOS 10.14.3