Setup Dependabot for automating dependencies updates

[p-r-a-v-i-n]

As discussed in #9881

PS: would be nice to get these automated

Which would be good for our requirement dependabot or renovate ? we already use dependabot so should we extend it ?

Yes I think we'd have to stick to dependabot as I don't think I have the ability to enable renovate on the encode org

[Copilot]

Pull request overview

This PR adds Dependabot configuration for automated Python dependency updates in Django REST Framework. As discussed in PR #9881, this extends the existing Dependabot setup (which currently only tracks GitHub Actions) to also monitor Python package dependencies.

Changes:

• Added pip package ecosystem configuration to Dependabot
• Configured dependency grouping to match the project's dependency-groups structure (test, docs, optional)
• Set weekly update schedule with 7-day cooldown, consistent with GitHub Actions configuration

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.