chore(deps): update nuxt typescript core packages to v2.15.6

[renovate[bot]]

This PR contains the following updates:

Package	Change	Age	Adoption	Passing	Confidence
@nuxt/types	2.15.5 -> 2.15.6
nuxt	2.15.5 -> 2.15.6

---

Release Notes

nuxt/nuxt.js

### [`v2.15.6`](https://togithub.com/nuxt/nuxt.js/releases/v2.15.6) [Compare Source](https://togithub.com/nuxt/nuxt.js/compare/v2.15.5...v2.15.6) ##### 🐛 Bug Fixes - `types` - [#​9270](https://togithub.com/nuxt/nuxt.js/issues/9270) Pin to `@types/webpack-dev-middleware@4.1.2` (resolves [#​9268](https://togithub.com/nuxt/nuxt.js/issues/9268))

---

Configuration

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

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

♻️ Rebasing: Renovate will not automatically rebase this PR, because other commits have been found.

🔕 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.