composer bump - Fix typo in the warning message (#10841)

Change warning text 'Alternatively you can use --dev-only to only bump dependencies within "require-dev"'
that said `--dev` instead of `--dev-only`.

src/Composer/Command/BumpCommand.php

@@ -126,7 +126,7 @@ protected function execute(InputInterface $input, OutputInterface $output)
             $contents = $composerJson->read();
             if (!isset($contents['type'])) {
                 $io->writeError('<warning>If your package is not a library, you can explicitly specify the "type" by using "composer config type project".</warning>');
-                $io->writeError('<warning>Alternatively you can use --dev to only bump dependencies within "require-dev".</warning>');
+                $io->writeError('<warning>Alternatively you can use --dev-only to only bump dependencies within "require-dev".</warning>');
             }
             unset($contents);
         }