Build against latest 5.2.x Spring Framework snapshot

[eleftherias]

Builds are failing on https://jenkins.spring.io/job/spring-security due to an incompatible feature in Spring Framework 5.3.0-SNAPSHOT.

We will temporarily build against the latest 5.2.x snapshot, since our dependency is on the Spring Framework 5.2.x line anyway.

[eleftherias]

This feature was added via 07f8154 and reverted via d91b153.