Change required version for drupal/bootstrap_styles to allow ^2

There is a v2 branch of bootstrap_styles (2.0.x-dev).

I'd like to test this in my project / create a patch against that branch but I cannot update bootstrap_styles because bootstrap_layout_builder has this in the composer.json under require:
"drupal/bootstrap_styles": "^1.0",

So I get this message:

Problem 1
    - drupal/bootstrap_layout_builder is locked to version 2.0.1 and an update of this package was not requested.
    - drupal/bootstrap_layout_builder 2.0.1 requires drupal/bootstrap_styles ^1.0 -> found drupal/bootstrap_styles[dev-1.0.x, 1.0.0-alpha1, ..., 1.0.x-dev (alias of dev-1.0.x)] but it conflicts with your root composer.json require (2.0.x-dev@dev).