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

Author: renovate[bot]

.github/workflows/tests.yml

@@ -18,7 +18,7 @@ jobs:
           - 22.4.1 # maintainence ends 2027-04-30
     steps:
       - uses: actions/checkout@v4
-      - uses: actions/setup-node@v4
+      - uses: actions/setup-node@v6
         with:
           node-version: ${{ matrix.node-version }}
       - run: npm install
@@ -30,7 +30,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
-      - uses: actions/setup-node@v4
+      - uses: actions/setup-node@v6
         with:
           node-version: 22.20.0
       - run: npm install