Bump actions/setup-node from 5 to 6

Bumps [actions/setup-node](https://github.com/actions/setup-node) from 5 to 6.
- [Release notes](https://github.com/actions/setup-node/releases)
- [Commits](actions/setup-node@v5...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] <[email protected]>

Author: dependabot[bot]

.github/workflows/build.yml

@@ -422,7 +422,7 @@ jobs:
         working-directory: app/build/macos/Build/Products/Release
         run: zip --symlinks -qr linwood-flow-macos.zip flow.app
       - name: Setup node
-        uses: actions/setup-node@v5
+        uses: actions/setup-node@v6
         with:
           node-version: 24
       - name: Install appdmg

.github/workflows/deploy.yml

@@ -20,7 +20,7 @@ jobs:
         with:
           package_json_file: docs/package.json
       - name: Use Node.js
-        uses: actions/setup-node@v5
+        uses: actions/setup-node@v6
         with:
           node-version: 24
           cache: "pnpm"