* Bump bootsnap from 1.6.0 to 1.8.1

Bumps [bootsnap](https://github.com/Shopify/bootsnap) from 1.6.0 to 1.8.1.
- [Release notes](https://github.com/Shopify/bootsnap/releases)
- [Changelog](https://github.com/Shopify/bootsnap/blob/master/CHANGELOG.md)
- [Commits](https://github.com/Shopify/bootsnap/compare/v1.6.0...v1.8.1)

---
updated-dependencies:
- dependency-name: bootsnap
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

* Remove deprecated bootsnap config options

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Claire <claire.github-309c@sitedethib.com>

By default, an unset RAILS_ENV is understood as RAILS_ENV=development.

However, this is not what most people expect, and due to development-only
dependencies, users are often left with confusing error messages.

This commit changes it so that an explicit RAILS_ENV is required, and
failing that, an error message is displayed before loading the app.

Co-authored-by: Claire <claire.github-309c@sitedethib.com>

Resolve #9490