Bump actions/setup-node from 4 to 6

Bumps [actions/setup-node](https://github.com/actions/setup-node) from 4 to 6.
- [Release notes](https://github.com/actions/setup-node/releases)
- [Commits](actions/setup-node@v4...v6)

---
updated-dependencies:
- dependency-name: actions/setup-node
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

.github/workflows/tests.yml

@@ -73,7 +73,7 @@ jobs:
                     extensions: curl, mbstring, zip, iconv, json, dom, fileinfo, tokenizer
                     coverage: none
 
-            -   uses: actions/setup-node@v4
+            -   uses: actions/setup-node@v6
                 with:
                     node-version: 22
 
@@ -112,7 +112,7 @@ jobs:
                     extensions: curl, mbstring, zip, iconv, json, dom, fileinfo, tokenizer
                     coverage: none
 
-            -   uses: actions/setup-node@v4
+            -   uses: actions/setup-node@v6
                 with:
                     node-version: 22