Merge pull request #15 from symfony-tools/flex-version

Remove Flex version in instructions

Author: fabpot

src/DiffRecipeVersionsCommand.php

@@ -62,7 +62,7 @@ protected function execute(InputInterface $input, OutputInterface $output): int
 
  2. Install the package(s) related to this recipe:
     ```sh
-    composer req 'symfony/flex:^1.16'
+    composer req symfony/flex
     composer req {$requires}
     ```