Add CI

.github/workflows/workflow.yml

@@ -0,0 +1,45 @@
+name: CI
+
+on:
+  push:
+    branches:
+      - master
+      - main
+  pull_request:
+
+jobs:
+  test:
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ubuntu-latest, macos-latest]
+        # for some reason, Windows cannot connect to Melpa on
+        # Emacs 27, so no Windows
+        emacs-version:
+          - 26.1
+          - 26.2
+          - 26.3
+          - 27.1
+          - 27.2
+          - 28.1
+          - snapshot
+
+    steps:
+    - uses: actions/checkout@v2
+
+    - uses: jcs090218/setup-emacs@master
+      with:
+        version: ${{ matrix.emacs-version }}
+
+    - uses: actions/setup-node@v2
+      with:
+        node-version: '16'
+
+    - uses: emacs-eask/setup-eask@master
+      with:
+        version: 'snapshot'
+
+    - name: Run tests
+      run:
+        make ci