chore(deps): update actions/setup-node action to v6

Author: renovate[bot]

.github/workflows/nodejs-test.yml

@@ -20,7 +20,7 @@ jobs:
         steps:
             - uses: actions/checkout@v5
             - name: Use Node.js ${{ matrix.node }}
-              uses: actions/setup-node@v5
+              uses: actions/setup-node@v6
               with:
                   node-version: ${{ matrix.node }}
             - name: npm install, build, and test

.github/workflows/release-please.yml

@@ -24,7 +24,7 @@ jobs:
               # a new release is created:
               if: ${{ steps.release.outputs.release_created }}
 
-            - uses: actions/setup-node@v5
+            - uses: actions/setup-node@v6
               with:
                   node-version: lts/*
                   registry-url: "https://registry.npmjs.org"