Transition to Github Actions

.github/workflows/stack-ci.yaml

@@ -0,0 +1,102 @@
+name: Tests
+on:
+  pull_request:
+  push:
+    branches:
+      - master
+
+jobs:
+  build:
+    name: CI
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        resolver:
+          [
+            "nightly-2023-06-27",
+            "lts-21.0",
+            "lts-20.26",
+            "lts-19.33",
+            "lts-18.28",
+            "lts-16.31",
+            "lts-14.27",
+            "lts-12.26",
+            "lts-11.22",
+            "lts-9.21",
+          ]
+        include:
+          - resolver: "nightly-2023-06-27"
+            os: ubuntu-latest
+            ghc: "9.6.2"
+            cabal: latest
+            stack: latest
+          - resolver: "lts-21.0"
+            os: ubuntu-latest
+            ghc: "9.4.5"
+            cabal: latest
+            stack: latest
+          - resolver: "lts-20.26"
+            os: ubuntu-latest
+            ghc: "9.2.5"
+            cabal: latest
+            stack: latest
+          - resolver: "lts-19.33"
+            os: ubuntu-latest
+            ghc: "9.0.2"
+            cabal: latest
+            stack: latest
+          - resolver: "lts-18.28"
+            os: ubuntu-latest
+            ghc: "8.10.7"
+            cabal: latest
+            stack: latest
+          - resolver: "lts-16.31"
+            os: ubuntu-latest
+            ghc: "8.8.4"
+            cabal: latest
+            stack: latest
+          - resolver: "lts-14.27"
+            os: ubuntu-latest
+            ghc: "8.6.5"
+            cabal: latest
+            stack: latest
+          - resolver: "lts-12.26"
+            os: ubuntu-latest
+            ghc: "8.4.4"
+            cabal: latest
+            stack: latest
+          - resolver: "lts-11.22"
+            os: ubuntu-latest
+            ghc: "8.2.2"
+            cabal: latest
+            stack: latest
+          - resolver: "lts-9.21"
+            os: ubuntu-latest
+            ghc: "8.0.2"
+            cabal: latest
+            stack: latest
+
+    steps:
+      - name: Setup GHC
+        uses: haskell/actions/setup@v2
+        with:
+          ghc-version: ${{ matrix.ghc }}
+          enable-stack: true
+          stack-version: ${{ matrix.stack }}
+          cabal-version: ${{ matrix.cabal }}
+
+      - name: Clone project
+        uses: actions/checkout@v3
+
+      - name: Cache dependencies
+        uses: actions/cache@v3
+        with:
+          path: ~/.stack
+          key: ${{ runner.os }}-${{ matrix.resolver }}-${{ hashFiles('stack.yaml') }}
+          restore-keys: |
+            ${{ runner.os }}-${{ matrix.resolver }}-
+
+      # This entirely avoids the caching of a GHC version.
+      - name: Build and run tests
+        run: "stack test --fast --no-terminal --resolver=${{ matrix.resolver }} --system-ghc"

stack.yaml

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+resolver: lts-21.0