title: Downgrade flutter version to avoid null-safety
body: <p>How can I downgrade the my version of flutter to avoid the null-safety?? I updated and this feature appears but Im using some packages like Badges and https that arent updated for null-safety and Im gettin several bugs to run my code.</p>
  <p>My pubspec:
  environment:
  sdk: &quot;&gt;=2.7.0 &lt;3.0.0&quot;</p>
  <p>Thanks!!</p>