Update deprecated gh actions

Author: grosscol

.github/workflows/ci.yml

@@ -13,15 +13,15 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        node-version: [16.x]
+        node-version: [20.x]
     steps:
     - uses: actions/checkout@v2
     - name: Use Node.js ${{ matrix.node-version }}
       uses: actions/setup-node@v2
       with:
         node-version: ${{ matrix.node-version }}
     - name: Cache Node.js modules
-      uses: actions/cache@v2
+      uses: actions/cache@v4
       with:
         path: ~/.npm
         key: ${{ runner.OS }}-node-${{ hashFiles('**/package-lock.json') }}