Remove code for legacy Process component versions

Author: bschultz

Dotenv.php

@@ -446,12 +446,7 @@ private function resolveCommands(string $value, array $loadedVars): string
                 throw new \LogicException('Resolving commands requires the Symfony Process component.');
             }
 
-            $process = method_exists(Process::class, 'fromShellCommandline') ? Process::fromShellCommandline('echo '.$matches[0]) : new Process('echo '.$matches[0]);
-
-            if (!method_exists(Process::class, 'fromShellCommandline') && method_exists(Process::class, 'inheritEnvironmentVariables')) {
-                // Symfony 3.4 does not inherit env vars by default:
-                $process->inheritEnvironmentVariables();
-            }
+            $process = Process::fromShellCommandline('echo '.$matches[0]);
 
             $env = [];
             foreach ($this->values as $name => $value) {

composer.json

@@ -23,7 +23,8 @@
         "symfony/process": "^5.4|^6.0"
     },
     "conflict": {
-        "symfony/console": "<5.4"
+        "symfony/console": "<5.4",
+        "symfony/process": "<5.4"
     },
     "autoload": {
         "psr-4": { "Symfony\\Component\\Dotenv\\": "" },