build(deps): bump fastify/workflows/.github/workflows/plugins-ci-package-manager.yml

Bumps [fastify/workflows/.github/workflows/plugins-ci-package-manager.yml](https://github.com/fastify/workflows) from 5 to 6.
- [Release notes](https://github.com/fastify/workflows/releases)
- [Commits](fastify/workflows@v5...v6)

---
updated-dependencies:
- dependency-name: fastify/workflows/.github/workflows/plugins-ci-package-manager.yml
  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/package-manager-ci.yml

@@ -21,4 +21,4 @@ jobs:
   test:
     permissions:
       contents: read
-    uses: fastify/workflows/.github/workflows/plugins-ci-package-manager.yml@v5
+    uses: fastify/workflows/.github/workflows/plugins-ci-package-manager.yml@v6