CI: use haskell/actions/setup.

actions/haskell-setup is no longer maintained.

.github/workflows/ci.yml

@@ -61,7 +61,7 @@ jobs:
     # need to install older cabal/ghc versions from ppa repository
 
     - name: Install recent cabal/ghc
-      uses: actions/setup-haskell@v1.1.3
+      uses: haskell/actions/setup@v1
       with:
         ghc-version: ${{ matrix.versions.ghc }}
         cabal-version: ${{ matrix.versions.cabal }}
@@ -108,7 +108,7 @@ jobs:
     - uses: actions/checkout@v2
 
     # We should have ghc 8.10, cabal, stack pre-installed
-    # - uses: actions/setup-haskell@v1.1.3
+    # - uses: haskell/actions/setup@v1
     #   with:
     #     enable-stack: true
     #     stack-version: 'latest'
@@ -157,7 +157,7 @@ jobs:
     - uses: actions/checkout@v2
 
     - name: Install recent cabal/ghc
-      uses: actions/setup-haskell@v1.1.3
+      uses: haskell/actions/setup@v1
       with:
         ghc-version: ${{ matrix.versions.ghc }}
         cabal-version: ${{ matrix.versions.cabal }}