Add Github actions

.github/workflows/ci.yaml

@@ -0,0 +1,20 @@
+name: CI
+on: [push, pull_request]
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        ghc: ['8.10', '8.8', '8.6']
+    steps:
+    - name: Checkout repository
+      uses: actions/[email protected]
+    - name: Setup haskell
+      uses: actions/[email protected]
+      with:
+        ghc-version: ${{ matrix.ghc }}
+    - name: Build euphoria
+      run: cabal v2-build
+    - name: Test euphoria
+      run: cabal v2-test