Merge branch '3.4' into 4.3

* 3.4:
  [Finder] Fixed docs
  Fix PR template
  Adjust pull request template for 5.0 branchout
  Update HttpKernel.php

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,6 +1,6 @@
 | Q             | A
 | ------------- | ---
-| Branch?       | 4.4 for features / 3.4 or 4.3 for bug fixes <!-- see below -->
+| Branch?       | master for features / 3.4, 4.3, 4.4 or 5.0 for bug fixes <!-- see below -->
 | Bug fix?      | yes/no
 | New feature?  | yes/no <!-- please update src/**/CHANGELOG.md files -->
 | Deprecations? | yes/no <!-- please update UPGRADE-*.md and src/**/CHANGELOG.md files -->
@@ -16,6 +16,5 @@ Additionally (see https://symfony.com/roadmap):
  - Never break backward compatibility (see https://symfony.com/bc).
  - Bug fixes must be submitted against the lowest maintained branch where they apply
    (lowest branches are regularly merged to upper ones so they get the fixes too.)
- - Features and deprecations must be submitted against branch 4.4.
- - Legacy code removals go to the master branch.
+ - Features and deprecations must be submitted against branch master.
 -->

src/Symfony/Component/Finder/Finder.php

@@ -793,7 +793,7 @@ private function searchInDirectory(string $dir): \Iterator
     /**
      * Normalizes given directory names by removing trailing slashes.
      *
-     * Excluding: (s)ftp:// wrapper
+     * Excluding: (s)ftp:// or ssh2.(s)ftp:// wrapper
      *
      * @param string $dir
      *

src/Symfony/Component/HttpKernel/HttpKernel.php

@@ -62,7 +62,7 @@ public function __construct(EventDispatcherInterface $dispatcher, ControllerReso
      */
     public function handle(Request $request, $type = HttpKernelInterface::MASTER_REQUEST, $catch = true)
     {
-        $request->headers->set('X-Php-Ob-Level', ob_get_level());
+        $request->headers->set('X-Php-Ob-Level', (string) ob_get_level());
 
         try {
             return $this->handleRaw($request, $type);