minor #15688 [Doc] Use new repo location (Goutte & Silex) in some readme.md (JakeFr)

This PR was merged into the 2.3 branch.

Discussion
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[Doc] Use new repo location (Goutte & Silex) in some readme.md

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets |
| License       | MIT
| Doc PR        |

Correct links to silex and goutte repos to the new organizations, respectively FriendsOfPHP and silexphp.
Not a bug fix, github.com redirects correctly, just typo.

Commits
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fa7fe56 use new repo location in some readme.md

src/Symfony/Component/BrowserKit/README.md

@@ -10,7 +10,7 @@ Resources
 ---------
 
 For a simple implementation of a browser based on an HTTP layer, have a look
-at [Goutte](https://github.com/fabpot/Goutte).
+at [Goutte](https://github.com/FriendsOfPHP/Goutte).
 
 For an implementation based on HttpKernelInterface, have a look at the
 [Client](https://github.com/symfony/symfony/blob/master/src/Symfony/Component/HttpKernel/Client.php)

src/Symfony/Component/Form/README.md

@@ -10,7 +10,7 @@ Resources
 
 Silex integration:
 
-https://github.com/fabpot/Silex/blob/master/src/Silex/Provider/FormServiceProvider.php
+https://github.com/silexphp/Silex/blob/master/src/Silex/Provider/FormServiceProvider.php
 
 Documentation:
 

src/Symfony/Component/Translation/README.md

@@ -24,7 +24,7 @@ Resources
 
 Silex integration:
 
-https://github.com/fabpot/Silex/blob/master/src/Silex/Provider/TranslationServiceProvider.php
+https://github.com/silexphp/Silex/blob/master/src/Silex/Provider/TranslationServiceProvider.php
 
 Documentation:
 

src/Symfony/Component/Validator/README.md

@@ -109,7 +109,7 @@ Resources
 
 Silex integration:
 
-https://github.com/fabpot/Silex/blob/master/src/Silex/Provider/ValidatorServiceProvider.php
+https://github.com/silexphp/Silex/blob/master/src/Silex/Provider/ValidatorServiceProvider.php
 
 Documentation: