Update dependency react-helmet to v6

[renovate[bot]]

This PR contains the following updates:

Package	Change	Age	Adoption	Passing	Confidence
react-helmet	^5 -> ^6.0.0
@types/react-helmet	5.0.16 -> 6.1.1

---

Release Notes

nfl/react-helmet

v6.1.0

Compare Source

Features

• Re-add Helmet as a default export (#​547)
  • Note: You may now choose import Helmet or import {Helmet}
• Updates react-fast-compare to get support for Preact (#​559)

v6.0.0

Compare Source

Features

• Bundle with Rollup instead of Webpack - As a result, the default export was removed and Helmet must now be imported as a named component - import {Helmet} from "react-helmet" (#​395)
• Replace deepEqual with isEqual (#​402)

---

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 these updates 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.

[hppRC]

react-helmet@v6 will break gatsby-plugin-react-helmet