Changes related to the next MeiliSearch release (v0.21.0)

[meili-bot]

This PR gathers the changes related to the next MeiliSearch release (v0.21.0) so that this package is ready when the official release is out.

⚠️ This PR should NOT be merged until:

• the next release of MeiliSearch (v0.21.0) is out.
• the docs-searchbar.js dependency has been released to be compatible with MeiliSearch v0.21.0. Once the release is out, the docs-searchbar.js version in this package should be upgraded and committed to this branch.

This PR is auto-generated for the pre-release week purpose. Exceptionally for this release, the pre-release time will be more than just one week.

[bidoubiwa]

bors merge

[bors[bot]]

Build succeeded:

• linter-check
• Tests (Node.js 12)
• Tests (Node.js 14)