Add AbstractCliBasedDriver::launchProcess()

This protected method is responsible for running the process responsible for sending the notification.
It will allow any developer that wants to override how the process in launched

src/Driver/AbstractCliBasedDriver.php

@@ -81,7 +81,7 @@ public function send(Notification $notification): bool
         }
 
         $process = new Process(array_merge([$binary], $arguments));
-        $process->run();
+        $this->launchProcess($process);
 
         return $this->handleExitCode($process);
     }
@@ -125,6 +125,11 @@ protected function isBinaryAvailable(): bool
         return $process->isSuccessful();
     }
 
+    protected function launchProcess(Process $process): void
+    {
+        $process->run();
+    }
+
     /**
      * Return whether the process executed successfully.
      */