.travis.yml: Update for current Debians and newer GHCs

Author: Deewiant

.travis.yml

@@ -1,12 +1,10 @@
 env:
- - CABALVER=1.18 GHCVER=7.4.1 # Debian 7
- - CABALVER=1.20 GHCVER=7.6.3 # Debian 8
- - CABALVER=1.18 GHCVER=7.8.4
- - CABALVER=1.22 GHCVER=7.10.3
- - CABALVER=1.24 GHCVER=8.0.2
+ - CABALVER=1.24 GHCVER=8.0.2 # Debian 9
  - CABALVER=1.24 GHCVER=8.2.2
- - CABALVER=2.2 GHCVER=8.4.3
- - CABALVER=2.4 GHCVER=8.6.3
+ - CABALVER=2.2 GHCVER=8.4.4 # Debian 10
+ - CABALVER=2.4 GHCVER=8.6.5
+ - CABALVER=3.0 GHCVER=8.8.3
+ - CABALVER=3.0 GHCVER=8.10.1
  - CABALVER=head GHCVER=head
 
 language: generic