Add @Configuration annotation to @AuthorizationServer annotation

[Ji Hun]

@EnableWebSecurity has @configuration, so just adding @EnableWebSecurity allows automatic setup, but @EnableAuthorizationServer does not have @configuration, so you need to add @configuration to proceed with the auto setup.

Generally, when using @Enable-related annotations, we think that using only that annotation will lead to automatic setup, so we would also like to add @configuration to @EnableAuthorizationServer

[Josh Cummings]

I think Spring Security may separate these in the future.

[Joe Grandja]

@hongji3354 This change cannot be applied based on comment.

[Ji Hun]

Thank you