Spring 6 compatibility

[Artur-]

Expected Behavior
This project should work with Spring 6

Current Behavior
The project uses Servlet < 5 with the javax namespace

Context
Spring 6 moved to Servlet 5 and Spring 6 M2 is already out.
When trying to test out Spring Boot 3 snapshot + Spring 6 M2 I ran into the issue that the oauth server cannot be used.

[jgrandja]

@Artur- Spring Authorization Server currently builds against Spring Security 5.5.3. We plan to upgrade to Spring Security 5.6.0 in the 0.3.0 release (gh-594).

We will upgrade to Spring Security 6.0 after it is released, which is planned for later this year.