minor #5824 Deprecate v2 (keradus)

This PR was squashed before being merged into the 2.19 branch.

Discussion
----------

Deprecate v2

Commits
-------

cfa2df6 Deprecate v2

Author: keradus

src/Console/WarningsDetector.php

@@ -39,8 +39,9 @@ public function __construct(ToolInfoInterface $toolInfo)
 
     public function detectOldMajor()
     {
-        // @TODO 2.99 to be activated with new MAJOR release
-        // $this->warnings[] = 'You are running PHP CS Fixer v2, which is not maintained anymore. Please update to v3.';
+        $currentMajorVersion = \intval(explode('.', Application::VERSION)[0], 10);
+        $nextMajorVersion = $currentMajorVersion + 1;
+        $this->warnings[] = "You are running PHP CS Fixer v{$currentMajorVersion}, which is not maintained anymore. Please update to v{$nextMajorVersion}.";
     }
 
     public function detectOldVendor()

tests/Smoke/CiIntegrationTest.php

@@ -140,13 +140,19 @@ public function testIntegration(
             $steps[4],
         ]);
 
+        $optionalDeprecatedVersionWarning = 'You are running PHP CS Fixer v2, which is not maintained anymore. Please update to v3.
+';
+
         $optionalIncompatibilityWarning = 'PHP needs to be a minimum version of PHP 5.6.0 and maximum version of PHP 7.4.*.
 Current PHP version: '.PHP_VERSION.'.
 Ignoring environment requirements because `PHP_CS_FIXER_IGNORE_ENV` is set. Execution may be unstable.
 ';
 
         $optionalXdebugWarning = 'You are running PHP CS Fixer with xdebug enabled. This has a major impact on runtime performance.
-If you need help while solving warnings, ask at https://gitter.im/PHP-CS-Fixer, we will help you!
+';
+
+        $optionalWarningsHelp = 'If you need help while solving warnings, ask at https://gitter.im/PHP-CS-Fixer, we will help you!
+
 ';
 
         /** @phpstan-ignore-next-line to avoid `Ternary operator condition is always true|false.` */
@@ -155,9 +161,11 @@ public function testIntegration(
             : 'PHP CS Fixer '.preg_quote(Application::VERSION, '/').' by Fabien Potencier and Dariusz Ruminski';
 
         $pattern = sprintf(
-            '/^(?:%s)?(?:%s)?%s\n%s\n%s\n([\.S]{%d})\n%s$/',
+            '/^(?:%s)?(?:%s)?(?:%s)?(?:%s)?%s\n%s\n%s\n([\.S]{%d})\n%s$/',
+            preg_quote($optionalDeprecatedVersionWarning, '/'),
             preg_quote($optionalIncompatibilityWarning, '/'),
             preg_quote($optionalXdebugWarning, '/'),
+            preg_quote($optionalWarningsHelp, '/'),
             $aboutSubpattern,
             preg_quote(sprintf('Runtime: PHP %s', PHP_VERSION), '/'),
             preg_quote('Loaded config default from ".php-cs-fixer.dist.php".', '/'),