minor symfony#45558 [Intl] Fix link not present (94noni)

This PR was merged into the 5.4 branch.

Discussion
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[Intl] Fix link not present

| Q             | A
| ------------- | ---
| Branch?       | 5.4
| Bug fix?      | no
| New feature?  | no

Ref https://github.com/symfony/symfony/edit/4.4/src/Symfony/Component/Intl/README.md

Commits
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12aec87 Fix link not present

Author: fabpot

src/Symfony/Component/Intl/README.md

@@ -17,3 +17,5 @@ Resources
    in the [main Symfony repository](https://github.com/symfony/symfony)
  * [Docker images with intl support](https://hub.docker.com/r/jakzal/php-intl)
    (for the Intl component development)
+
+[0]: https://php.net/intl.setup