ci: add github actions

.github/dependabot.yml

@@ -0,0 +1,8 @@
+version: 2
+updates:
+  - package-ecosystem: npm
+    directory: "/"
+    schedule:
+      interval: daily
+    open-pull-requests-limit: 5
+    versioning-strategy: increase-if-necessary

.github/workflows/node.js.yml

@@ -0,0 +1,25 @@
+name: Node.js CI
+
+on:
+  push:
+    branch: master
+  pull_request:
+    branch: master
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+
+    strategy:
+      matrix:
+        node-version: [20.x]
+
+    steps:
+    - uses: actions/checkout@v2
+    - name: Use Node.js ${{ matrix.node-version }}
+      uses: actions/setup-node@v1
+      with:
+        node-version: ${{ matrix.node-version }}
+    - run: npm ci
+    - run: npm run test