Provides Mercure integration for Symfony Notifier.

MERCURE_DSN=mercure://HUB_ID?topic=TOPIC

where:

• HUB_ID is the Mercure hub id
• TOPIC is the topic IRI (optional, default: https://symfony.com/notifier. Could be either a single topic: topic=https://foo or multiple topics: topic[]=/foo/1&topic[]=https://bar)

• Contributing
• Report issues and send Pull Requests in the main Symfony repository