CI, cache npm

Author: PierreBrisorgueil

.github/workflows/CI.yml

@@ -20,6 +20,7 @@ jobs:
         uses: actions/setup-node@v3
         with:
           node-version: ${{ matrix.node-version }}
+          cache: 'npm'
       - name: Start Mongo
         uses: supercharge/[email protected]
       - name: Run tests