Bump gutenberg from ee2fb29 to 8a815ee

Bumps [gutenberg](https://github.com/WordPress/gutenberg) from `ee2fb29` to `8a815ee`.
- [Release notes](https://github.com/WordPress/gutenberg/releases)
- [Commits](WordPress/gutenberg@ee2fb29...8a815ee)

---
updated-dependencies:
- dependency-name: gutenberg
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>