nightly: don't need to apt-get install. ci: test on ghc 8.10.1.

.github/workflows/ci.yml

@@ -53,6 +53,8 @@ jobs:
             cabal: '2.4'
           - ghc: '8.8.1'
             cabal: '3.0'
+          - ghc: '8.10.1'
+            cabal: '3.2'
     steps:
     - uses: actions/checkout@v1
 

.github/workflows/nightly.yml

@@ -10,11 +10,6 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v1
-    - name: Install recent cabal/ghc
-      run: |
-          sudo add-apt-repository ppa:hvr/ghc
-          sudo apt-get update
-          sudo apt-get install ghc-8.8.1 cabal-install-3.0
     - name: Install dependencies
       run: |
           export PATH=/opt/cabal/3.0/bin:/opt/ghc/8.8.1/bin:$PATH