Update dependency gradle to v6.9

[renovate[bot]]

This PR contains the following updates:

Package	Update	Change
gradle (source)	minor	6.8.3 -> 6.9

---

Release Notes

gradle/gradle

### [`v6.9`](https://togithub.com/gradle/gradle/compare/v6.8.3...v6.9.0)

---

Configuration

📅 Schedule: At any time (no schedule defined).

🚦 Automerge: Disabled by config. Please merge this manually once you are satisfied.

♻ Rebasing: Whenever PR becomes conflicted, or you tick the rebase/retry checkbox.

🔕 Ignore: Close this PR and you won't be reminded about this update again.

---

• [ ] If you want to rebase/retry this PR, check this box.

---

This PR has been generated by WhiteSource Renovate. View repository job log here.