Spring Security 5.4.x Snapshot Build Should Point to Other Maintenance Branches

Currently, the 5.4.x snapshot build points to the latest Spring 5+, Reactor 1.1+, and others that would imply a minor release in a maintenance branch.

They should be adjusted as follows:

Spring 5+ -> Spring 5.2+ Reactor 2020+ -> Reactor Dysprosium-BUILD-SNAPSHOT RSocket 1.1+ -> RSocket 1.0+ Spring Boot 2.4+ -> Spring Boot 2.3+

This is similar to what was already done in 66ceb4dc1093d5d746af7a4fc932130f19d9384a

Comment From: jzheaux

Closed via 574073d93f79a97acfcfdb6488228f7a7536230b