[php] Add PSR-12 rule set

Created by: ybelenko

I've added PSR-12 rule set to Php-CS-Fixer config since it's officially supported now. The config file has been renamed to .php-cs-fixer.dist.php to be able to overwrite it with local config file without dist part.

I don't know why we have so many rules since we agreed to follow PSR-12 only at the first place. New config:

/**
 * @generated
 * @link https://github.com/FriendsOfPHP/PHP-CS-Fixer/blob/HEAD/doc/config.rst
 */
$finder = PhpCsFixer\Finder::create()
    ->in(__DIR__)
    ->exclude('vendor')
    ->exclude('test')
    ->exclude('tests')
;

$config = new PhpCsFixer\Config();
return $config->setRules([
        '@PSR12' => true,
        'phpdoc_order' => true,
        'array_syntax' => [ 'syntax' => 'short' ],
        'strict_comparison' => true,
        'strict_param' => true,
        'no_trailing_whitespace' => false,
        'no_trailing_whitespace_in_comment' => false,
        'braces' => false,
        'single_blank_line_at_eof' => false,
        'blank_line_after_namespace' => false,
        'no_leading_import_slash' => false,
    ])
    ->setFinder($finder)
;

If somebody knows why we have disabled:

        'braces' => false,
        'single_blank_line_at_eof' => false,
        'blank_line_after_namespace' => false,

Also added rule no_leading_import_slash => false because there are model classes with leadings slashes in imports. No clue why, but still.

Fixer run output:

vendor/bin/php-cs-fixer fix --allow-risky=yes -vv
PHP CS Fixer 3.8.0 BerSzcz against war! by Fabien Potencier and Dariusz Ruminski.
PHP runtime: 8.0.16
Loaded config default from "/Users/ybelenko/Sites/openapi-generator/samples/client/petstore/php/OpenAPIClient-php/.php-cs-fixer.dist.php".
............................................................                                                                                    60 / 60 (100%)
Legend: ?-unknown, I-invalid file syntax (file ignored), S-skipped (cached or empty file), .-no changes, F-fixed, E-error

Fixed all files in 2.246 seconds, 28.000 MB memory used

I would remove the old .php_cs file from samples right in current PR, but the CI workflow will be failed instantly...

Related #4726

cc @jebentier @dkarlovi @mandrean @jfastnacht @renepardon

PR checklist

• Read the contribution guidelines.
• Pull Request title clearly describes the work in the pull request and Pull Request description provides details about how to validate the work. Missing information here may result in delayed response from the community.
• Run the following to build the project and update samples:

  ./mvnw clean package 
  ./bin/generate-samples.sh
  ./bin/utils/export_docs_generators.sh

  Commit all changed files. This is important, as CI jobs will verify all generator outputs of your HEAD commit as it would merge with master. These must match the expectations made by your contribution. You may regenerate an individual generator by passing the relevant config(s) as an argument to the script, for example ./bin/generate-samples.sh bin/configs/java*. For Windows users, please run the script in Git BASH.
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modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PhpClientCodegen.java

@@ -108,7 +108,7 @@ public class PhpClientCodegen extends AbstractPhpCodegen {
         supportingFiles.add(new SupportingFile("README.mustache", "", "README.md"));
         supportingFiles.add(new SupportingFile("phpunit.xml.mustache", "", "phpunit.xml.dist"));
         supportingFiles.add(new SupportingFile(".travis.yml", "", ".travis.yml"));
-        supportingFiles.add(new SupportingFile(".php_cs", "", ".php_cs"));
+        supportingFiles.add(new SupportingFile(".php-cs-fixer.dist.php", "", ".php-cs-fixer.dist.php"));
         supportingFiles.add(new SupportingFile("git_push.sh.mustache", "", "git_push.sh"));
     }
 }

modules/openapi-generator/src/main/resources/php/.php-cs-fixer.dist.php

 <?php
 
-return PhpCsFixer\Config::create()
-    ->setUsingCache(true)
-    ->setRules([
-        '@PSR2' => true,
-        'ordered_imports' => true,
+/**
+ * @generated
+ * @link https://github.com/FriendsOfPHP/PHP-CS-Fixer/blob/HEAD/doc/config.rst
+ */
+$finder = PhpCsFixer\Finder::create()
+    ->in(__DIR__)
+    ->exclude('vendor')
+    ->exclude('test')
+    ->exclude('tests')
+;
+
+$config = new PhpCsFixer\Config();
+return $config->setRules([
+        '@PSR12' => true,
         'phpdoc_order' => true,
         'array_syntax' => [ 'syntax' => 'short' ],
         'strict_comparison' => true,
@@ -14,10 +23,7 @@ return PhpCsFixer\Config::create()
         'braces' => false,
         'single_blank_line_at_eof' => false,
         'blank_line_after_namespace' => false,
+        'no_leading_import_slash' => false,
     ])
-    ->setFinder(
-        PhpCsFixer\Finder::create()
-        ->exclude('test')
-        ->exclude('tests')
-        ->in(__DIR__)
-    );
+    ->setFinder($finder)
+;

modules/openapi-generator/src/main/resources/php/ApiException.mustache

@@ -30,7 +30,6 @@ use \Exception;
  */
 class ApiException extends Exception
 {
-
     /**
      * The HTTP body of the server response either as Json or string.
      *

modules/openapi-generator/src/main/resources/php/HeaderSelector.mustache

@@ -30,7 +30,6 @@ use \Exception;
  */
 class HeaderSelector
 {
-
     /**
      * @param string[] $accept
      * @param string[] $contentTypes

modules/openapi-generator/src/main/resources/php/composer.mustache

@@ -33,7 +33,7 @@
     },
     "require-dev": {
         "phpunit/phpunit": "^8.0 || ^9.0",
-        "friendsofphp/php-cs-fixer": "^2.12"
+        "friendsofphp/php-cs-fixer": "^3.5"
     },
     "autoload": {
         "psr-4": { "{{escapedInvokerPackage}}\\" : "{{srcBasePath}}/" }