update github actions, ready for node16 deprecation

.github/workflows/ci.yml

@@ -6,28 +6,28 @@ jobs:
     name: Lint and test
     runs-on: ubuntu-latest
     steps:
-    - name: Check out code
-      uses: actions/checkout@v3
+      - name: Check out code
+        uses: actions/checkout@v4
 
-    - name: Setup nodejs
-      uses: actions/setup-node@v3
-      with:
-        node-version: '18'
+      - name: Setup nodejs
+        uses: actions/setup-node@v4
+        with:
+          node-version: "20"
 
-    - name: Install dependencies
-      run: npm ci
+      - name: Install dependencies
+        run: npm ci
 
-    - name: Check style with prettier
-      run: npm run format-check
+      - name: Check style with prettier
+        run: npm run format-check
 
-    - name: Run tests
-      run: npm test
+      - name: Run tests
+        run: npm test
 
-    - name: Compare the expected and actual dist/ directories
-      run: |
-        npm run build
-        if [ "$(git diff --ignore-blank-lines --ignore-space-at-eol dist/ | wc -l)" -gt "0" ]; then
-          echo "Detected uncommitted changes after build.  See status below:"
-          git diff
-          exit 1
-        fi
+      - name: Compare the expected and actual dist/ directories
+        run: |
+          npm run build
+          if [ "$(git diff --ignore-blank-lines --ignore-space-at-eol dist/ | wc -l)" -gt "0" ]; then
+            echo "Detected uncommitted changes after build.  See status below:"
+            git diff
+            exit 1
+          fi