Update actions/setup-node action to v6 (#9)

Author: renovate[bot]

.github/workflows/npm_test.yml

@@ -46,7 +46,7 @@ jobs:
         uses: actions/checkout@v5
 
       - name: Setup Node.js
-        uses: actions/setup-node@v5
+        uses: actions/setup-node@v6
         with:
           node-version-file: '.nvmrc'
           cache: 'yarn'