Please can you verify that the OAuth 2 implicit grant flow is not used by the plugin or in case the plugin makes use of it, the plugin is fixed?

Notes:

GitLab 14.0 deprecates the OAuth 2 implicit grant flow. Existing OAuth implicit grant flows will become unsupported in GitLab 14.4: https://docs.gitlab.com/ee/api/oauth2.html#implicit-grant-flow
supported flows: https://docs.gitlab.com/ee/api/oauth2.html#supported-oauth2-flows
14.4 comming (2021-10-22): https://about.gitlab.com/upcoming-releases/