Update dependency fluent-plugin-elasticsearch to v5.2.1

This MR contains the following updates:

Package	Type	Update	Change
fluent-plugin-elasticsearch	ironbank-rubygems	patch	5.2.0 -> 5.2.1

---

Configuration

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

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

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

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

---

• If you want to rebase/retry this MR, click this checkbox.

---

This MR has been generated by Renovate Bot.