Update ghcr.io/mend/renovate-ce Docker tag to v9

No problems upgrading the Docker container with a Docker compose yaml file within Portainer and by means of Portainer DevOps resp. GitOps with dependency update facilitated by Mend's Renovate Bot itself.

This MR contains the following updates:

Package	Update	Change
ghcr.io/mend/renovate-ce	major	`8.7.0-full` -> `9.0.0-full`

Release Notes

mend/renovate-ce-ee (ghcr.io/mend/renovate-ce)

`v9.0.0`

Compare Source

What's Changed

docs: document GitLab version for automatic webhook creation by @justo-mend in https://github.com/mend/renovate-ce-ee/pull/612
Update reporting-apis.md by @nkala1 in https://github.com/mend/renovate-ce-ee/pull/615
chore(deps): update ghcr.io/mend/renovate-ce docker tag to v8.7.0 by @renovate in https://github.com/mend/renovate-ce-ee/pull/604
docs: Create read-only-fs.md by @rarkins in https://github.com/mend/renovate-ce-ee/pull/592
chore(deps): update update mend renovate docker images to v9 (major) by @renovate in https://github.com/mend/renovate-ce-ee/pull/618

New Contributors

@nkala1 made their first contribution in https://github.com/mend/renovate-ce-ee/pull/615

Full Changelog: https://github.com/mend/renovate-ce-ee/compare/8.7.0...9.0.0

App

fix: Gitlab webhooks improvements: validate existing webhooks by name or URL
- Allows Gitlab users to use automatic webhook installation with versions prior to v17.1
fix: remove default onboarding config
- remove RENOVATE_ONBOARDING_CONFIG from the docker images
feat: add task summary to task_queue_history
feat: Read-only File Systems support (see docs for more details)
feat: update renovate to v39 (major)
- Docs
- Full change log
- 39.0.0 breaking changes
  - branchNameStrict: Branch names with multiple forward slashes will change if branchNameStrict=true
  - deps: Renovate sidecard images will default to use Ubuntu 24.04 instead of 20.04, and use User ID 12021 instead of 1000
  - deps: The Renovate full image now uses Ubuntu 24.04, Python 3.13 and Node v22
  - github: Renovate will now prefer squash merges over others in GitHub, if they are allowed.
  - Dockerfile: Renovate -full images will now use binarySource=global. Set RENOVATE_BINARY_SOURCE=install to revert to dynamic tool installation.
  - Renovate Docker images will now be based on Node.js v22 instead of v20