2.3.x-dev not compatible with D9

Problem/Motivation

After 📌 GitLab CI: Fix phpcs, eslint, and cspell tests Fixed , and the addition of a comma after every multi-line function declaration, this module is no longer compatible with the PHP version for Drupal 9.

Recent failed pipelines after commit

• https://git.drupalcode.org/project/flood_control/-/pipelines/189762
• https://git.drupalcode.org/project/flood_control/-/pipelines/189766

Steps to reproduce

Check out the tests for D9 which are now all failing with PHP syntax errors. Drupal 9 runs tests on PHP 7.4

Drupal: 9.5.11
PHP 7.4.28 (cli) (built: Jun 1 2022 23:17:36) ( NTS )

@see https://git.drupalcode.org/project/flood_control/-/jobs/1763896

Proposed resolution

- Cut a new branch version - 2.4.x? 3.0.x? for D10 (D11?) only
- Update testing targets in 2.3.x and 2.4.x/3.0.x branch to avoid running tests on releases that will not work

Remaining tasks

All of the above.

User interface changes

None.

API changes

None.

Data model changes

None.