chore: update GitHub Actions to use latest versions

Updated the GitHub Actions workflow to use the latest versions of
actions/checkout and actions/setup-node. Also, changed the node version
to 20.x and replaced 'npm install' with 'npm ci' for faster and more
reliable builds.

.github/workflows/main.yml

@@ -5,14 +5,11 @@ on:
 jobs:
   test:
     runs-on: ubuntu-latest
-    strategy:
-      matrix:
-        node-version: [10.x, 12.x, 14.x, 15.x]
 
     steps:
-      - uses: actions/checkout@v2
-      - uses: actions/setup-node@v1
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
         with:
-          node-version: ${{ matrix.node-version }}
-      - run: npm install
+          node-version: "20.x"
+      - run: npm ci
       - run: npm test