title: Invalid preceding regular expression git secret
body: <p>I am trying to use awslabs/git-secrets on windows. When I add regex like <br>
  <code>(?=.*\\d)(?=.*[a-z])(?=.*[A-Z])(?=.*[@$%&amp;*]).{8,}</code>
  and try to scan it throws an fatal error <strong>Invalid preceding regular expression</strong>. After trying to understand cause of error I found that if <strong>(?</strong> are wrote together it throws an error. I am trying to add regex for validating password with one uppercase,lowercase,digit and special character.
  <br>
  Thanks in advance</p>