minor #49107 [6.2] Remove mentions of v6.1 backers (nicolas-grekas)

This PR was merged into the 6.2 branch.

Discussion
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[6.2] Remove mentions of v6.1 backers

| Q             | A
| ------------- | ---
| Branch?       | 6.2
| Bug fix?      | no
| New feature?  | no
| Deprecations? | no
| Tickets       | -
| License       | MIT
| Doc PR        | -

Their sponsoring terms for v6.1 ended. Thanks to them! If you read this message, please consider taking over. Every company using Symfony can afford sponsoring one component for at least one version.

- Fulgens for Runtime v6.1 /cc `@alexandre`-castelain
- Prisma Media for HttpClient v6.1 /cc `@GromNaN`
- Mercure.rocks for Notifier v6.1 /cc `@dunglas`
- SensioLabs for Process /cc `@Jean`-Beru `@hadriengem` et al.

Commits
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0e13f98eb4 [6.2] Remove mentions of v6.1 backers

Author: nicolas-grekas

README.md

@@ -3,23 +3,6 @@ HttpClient component
 
 The HttpClient component provides powerful methods to fetch HTTP resources synchronously or asynchronously.
 
-Sponsor
--------
-
-The Httpclient component for Symfony 6.1 is [backed][1] by [Prisma Media][2].
-
-Prisma Media has become in 40 years the n°1 French publishing group, on print and
-digitally, with 20 flagship brands of the news magazines : Femme Actuelle, GEO,
-Capital, Gala or Télé-Loisirs… Today, more than 42 million French people are in
-contact with one of our brand each month, either by leafing through a magazine,
-surfing the web, subscribing one our mobile or tablet application or listening to
-our podcasts' series. Prisma Media has successfully transformed one's business
-model : from a historic player in the world of paper, it has become in 5 years
-one of the first publishers of multi-media editorial content, and one of the
-first creators of digital solutions.
-
-Help Symfony by [sponsoring][3] its development!
-
 Resources
 ---------
 
@@ -28,7 +11,3 @@ Resources
  * [Report issues](https://github.com/symfony/symfony/issues) and
    [send Pull Requests](https://github.com/symfony/symfony/pulls)
    in the [main Symfony repository](https://github.com/symfony/symfony)
-
-[1]: https://symfony.com/backers
-[2]: https://www.prismamedia.com
-[3]: https://symfony.com/sponsor