Fix macos ci and, add lts-20/22, remove lts-14 (#1839)

* install stack of macos as it is no longer included
ghc 8 not happy no macos-latest
nightly (seemingly there to target 9.0) replaced with higher lts versions

* update checkout version

* no long test on lts-14
#1838 will drop support for ghc 8.6

.github/workflows/tests.yml

@@ -15,23 +15,20 @@ jobs:
       matrix:
         os: [ubuntu-latest, macos-latest, windows-latest]
         args:
-        #- "--resolver nightly"
-        - "--resolver nightly-2022-02-11"
+        - "--resolver lts-22"
+        - "--resolver lts-20"
         - "--resolver lts-18"
         - "--resolver lts-16"
-        - "--resolver lts-14"
-        # Bugs in GHC make it crash too often to be worth running
         exclude:
-          - os: windows-latest
-            args: "--resolver nightly"
+          # llvm too new on macos-latest for ghc 8
           - os: macos-latest
-            args: "--resolver lts-16"
+            args: "--resolver lts-18"
           - os: macos-latest
-            args: "--resolver lts-14"
+            args: "--resolver lts-16"
 
     steps:
       - name: Clone project
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
 
 # Getting weird OS X errors...
 #      - name: Cache dependencies
@@ -42,6 +39,16 @@ jobs:
 #          restore-keys: |
 #            ${{ runner.os }}-${{ matrix.resolver }}-
 
+      - name: Install stack if needed
+        shell: bash
+        run: |
+            set -ex
+            if [[ "${{ matrix.os }}" == "macos-latest" ]]
+            then
+                # macos-latest does not include Haskell tools as of 2024-05-06.
+              curl -sSL https://get.haskellstack.org/ | sh
+            fi
+
       - name: Build and run tests
         shell: bash
         run: |