Added github-actions workflow

Author: coot

.github/workflows/cabal.project.ci

@@ -0,0 +1,15 @@
+documentation: True
+tests:         True
+benchmarks:    True
+
+package io-classes
+  ghc-options: -Werror
+  flags: +asserts
+
+package strict-stm
+  ghc-options: -Werror
+  flags: +asserts
+
+package io-sim
+  ghc-options: -Werror
+  flags: +asserts

.github/workflows/haskell.yml

@@ -0,0 +1,41 @@
+name: Haskell CI
+
+on: [push]
+
+jobs:
+  build:
+    runs-on: ${{ matrix.os }}
+
+    strategy:
+      fail-fast: false
+      matrix:
+        ghc: ["8.10.7", "9.2.2"]
+        os: [ubuntu-20.04, macos-latest, windows-latest]
+
+    steps:
+    - name: "Setup haskell"
+      uses: haskell/actions/setup@v1
+      id: setup-haskell
+      with:
+        ghc-version: ${{ matrix.ghc }}
+        cabal-version: 3.6.2.0
+
+    - uses: actions/checkout@v2
+
+    - name: "Configure cabal.project.local"
+      run: |
+        cat ./.github/workflows/cabal.project.local > ./cabal.project.local
+        cat ./cabal.project.local
+
+    - name: Build dependencies
+      run: cabal build --only-dependencies all
+
+    - name: Build projects [build]
+      run: cabal build all
+
+    - name: io-classes [test]
+      run: cabal run io-classes:test
+
+    - name: io-sim [test]
+      run: cabal run io-sim:test
+