Update dependency i18next to v21.9.0

[renovate[bot]]

This PR contains the following updates:

Package	Change	Age	Adoption	Passing	Confidence
i18next (source)	21.8.16 -> 21.9.0

---

Release Notes

i18next/i18next

### [`v21.9.0`](https://togithub.com/i18next/i18next/blob/HEAD/CHANGELOG.md#​2190) [Compare Source](https://togithub.com/i18next/i18next/compare/v21.8.16...v21.9.0) - Add Customizable Retry Logic [1810](https://togithub.com/i18next/i18next/pull/1810) - types: extend compatibilityJSON with v4

---

Configuration

📅 Schedule: Branch creation - At any time (no schedule defined), Automerge - At any time (no schedule defined).

🚦 Automerge: Enabled.

♻ 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, click this checkbox.

---

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

[cloudflare-workers-and-pages[bot]]

Deploying with    Cloudflare Pages

Latest commit:	3dcec4a
Status:	✅  Deploy successful!
Preview URL:	https://aafd49b9.kevink-dev.pages.dev
Branch Preview URL:	https://renovate-i18next-21-x.kevink-dev.pages.dev

View logs