minor symfony#47915 [Notifier] Update README for FreeMobile (ker0x)

This PR was merged into the 5.4 branch.

Discussion
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[Notifier] Update README for FreeMobile

| Q             | A
| ------------- | ---
| Branch?       | 5.4
| Bug fix?      | no
| New feature?  | no <!-- please update src/**/CHANGELOG.md files -->
| Deprecations? | no <!-- please update UPGRADE-*.md and src/**/CHANGELOG.md files -->
| Tickets       | -
| License       | MIT
| Doc PR        | -

Commits
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f0dc4b2 [Notifier] Update README for FreeMobile

Author: nicolas-grekas

src/Symfony/Component/Notifier/Bridge/FreeMobile/README.md

@@ -10,15 +10,15 @@ DSN example
 -----------
 
 ```
-FREE_MOBILE_DSN=freemobile://LOGIN:PASSWORD@default?phone=PHONE
+FREE_MOBILE_DSN=freemobile://LOGIN:API_KEY@default?phone=PHONE
 ```
 
 where:
  - `LOGIN` is your Free Mobile login
- - `PASSWORD` is the token displayed in your account
+ - `API_KEY` is the API key displayed in your account
  - `PHONE` is your Free Mobile phone number
 
-See your account info at https://mobile.free.fr/moncompte/index.php?page=options
+See your account info at https://mobile.free.fr/account/mes-options/notifications-sms
 
 Resources
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