minor #17969 [HttpCache] Inject $env in example (HypeMC)

This PR was merged into the 6.2 branch.

Discussion
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[HttpCache] Inject `$env` in example

A sort of followup to #17639, IMO makes the example a bit clearer.

Commits
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7ae2f94 [HttpCache] Inject $env in example

Author: javiereguiluz

http_cache.rst

@@ -114,7 +114,7 @@ Use the ``framework.http_cache`` option to enable the proxy for the
         // config/packages/framework.php
         use Symfony\Config\FrameworkConfig;
 
-        return static function (FrameworkConfig $framework) use ($env) {
+        return static function (FrameworkConfig $framework, string $env) {
             if ('prod' === $env) {
                 $framework->httpCache()->enabled(true);
             }