CI: bump compiler test matrix

Author: acowley

.github/workflows/ci.yml

@@ -13,12 +13,13 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest]
-        cabal: ["3.2"]
+        cabal: ["3.6"]
         ghc:
-          - "8.0.2"
-          - "8.2.2"
-          - "8.4.2"
-          - "8.10.4"
+          - "8.6.5"
+          - "8.8.4"
+          - "8.10.7"
+          - "9.0.2"
+          - "9.2.1"
 
     steps:
     - uses: actions/checkout@v2
@@ -63,8 +64,8 @@ jobs:
       # only test stack with one OS and one GHC version; if it works with
       # cabal, it probably also works with stack.
       matrix:
-        stack: ["2.3.1"]
-        ghc: ["8.0.2"]
+        stack: ["2.7.3"]
+        ghc: ["8.10.7"]
 
     steps:
     - uses: actions/checkout@v2