update travis to more recent ghc version

Author: juhp

.travis.yml

@@ -13,15 +13,15 @@ before_cache:
 
 matrix:
   include:
-    - env: CABALVER=1.18 GHCVER=7.8.4
-      compiler: ": #GHC 7.8.4"
-      addons: {apt: {packages: [cabal-install-1.18,ghc-7.8.4], sources: [hvr-ghc]}}
-    - env: CABALVER=1.22 GHCVER=7.10.2
-      compiler: ": #GHC 7.10.2"
-      addons: {apt: {packages: [cabal-install-1.22,ghc-7.10.2], sources: [hvr-ghc]}}
+    - env: GHCVER=8.8.4
+      compiler: ": #GHC 8.8.4"
+      addons: {apt: {packages: [cabal-install,ghc-8.8.4], sources: [hvr-ghc]}}
+    - env: GHCVER=8.10.7
+      compiler: ": #GHC 8.10.4"
+      addons: {apt: {packages: [cabal-install,ghc-8.10.4], sources: [hvr-ghc]}}
     - env: CABALVER=1.24 GHCVER=8.0.1
-      compiler: ": #GHC 8.0.1"
-      addons: {apt: {packages: [cabal-install-1.24,ghc-8.0.1], sources: [hvr-ghc]}}
+      compiler: ": #GHC 9.0.1"
+      addons: {apt: {packages: [cabal-install,ghc-9.0.1], sources: [hvr-ghc]}}
 
 before_install:
  - unset CC
@@ -78,4 +78,4 @@ script:
  - SRC_TGZ=$(cabal info . | awk '{print $2;exit}').tar.gz &&
    (cd dist && cabal install --force-reinstalls "$SRC_TGZ")
 
-# EOF
+# EOF