feature #22296 Bump monolog to 1.19 and use the agent regex const from parent (redthor)

This PR was merged into the 3.3-dev branch.

Discussion
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Bump monolog to 1.19 and use the agent regex const from parent

See #22264

| Q             | A
| ------------- | ---
| Branch?       | master
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | refer to #22264
| License       | MIT
| Doc PR        |

Bump monolog and use const from parent. See https://github.com/symfony/symfony/issues/22264#issuecomment-291524038

I went for `static` instead of `self` in case anyone wanted to easily override just the agent string.

Commits
-------

69f9586fd5 Bump monolog to 1.19 and use the agent regex const from parent, see #22264

src/Symfony/Bridge/Monolog/Handler/ChromePhpHandler.php

@@ -41,7 +41,7 @@ class ChromePhpHandler extends BaseChromePhpHandler
             return;
         }
 
-        if (!preg_match('{\b(?:Chrome/\d+(?:\.\d+)*|HeadlessChrome|Firefox/(?:4[3-9]|[5-9]\d|\d{3,})(?:\.\d)*)\b}', $event->getRequest()->headers->get('User-Agent'))) {
+        if (!preg_match(static::USER_AGENT_REGEX, $event->getRequest()->headers->get('User-Agent'))) {
             $this->sendHeaders = false;
             $this->headers = array();
 

src/Symfony/Bridge/Monolog/composer.json

@@ -17,7 +17,7 @@
     ],
     "require": {
         "php": ">=5.5.9",
-        "monolog/monolog": "~1.11",
+        "monolog/monolog": "~1.19",
         "symfony/http-kernel": "~2.8|~3.0"
     },
     "require-dev": {