Update version for the next release (v0.9.0)

[meili-bot]

This PR is auto-generated.

The automated script updates the version of meilisearch-rails to a new version: "v0.9.0"

[bors[bot]]

Build succeeded:

• integration-tests (Rails 5.2 with Ruby 2.6)
• integration-tests (Rails 5.2 with Ruby 2.7)
• integration-tests (Rails 6.1 with Ruby 2.6)
• integration-tests (Rails 6.1 with Ruby 2.7)
• integration-tests (Rails 6.1 with Ruby 3.0)
• integration-tests (Rails 6.1 with Ruby 3.1)
• integration-tests (Rails 7 with Ruby 2.7)
• integration-tests (Rails 7 with Ruby 3.0)
• integration-tests (Rails 7 with Ruby 3.1)
• linter-check
• smoke-test