[Intl] Fixed dependency on the Icu component to allow the installation of version 1.0.0-BETA1

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #8035
| License       | MIT
| Doc PR        | -

This implements @Seldaek's suggestion made in #8035 and hopefully fixes this ticket. The ticket would probably also be fixed by composer/composer#1881.