travis: Update compilers and build platform

Author: erikd

.travis.yml

@@ -1,11 +1,13 @@
-# language: haskell
+sudo: required
+language: c
 
-# See http://www.reddit.com/r/haskell/comments/1os3f6/how_to_use_travisci_with_multiple_ghc_versions/
+os: linux
+dist: xenial
 
 env:
  - GHCVER=7.10.3
- - GHCVER=8.0.1
- - GHCVER=8.2.1
+ - GHCVER=8.0.2
+ - GHCVER=8.2.2
 
 before_install:
  - sudo add-apt-repository -y ppa:hvr/ghc