Bump org.springframework.security:spring-security-bom (#9425)

Bumps [org.springframework.security:spring-security-bom](https://github.com/spring-projects/spring-security) from 6.4.0-M2 to 6.4.0-SNAPSHOT.
- [Release notes](https://github.com/spring-projects/spring-security/releases)
- [Changelog](https://github.com/spring-projects/spring-security/blob/main/RELEASE.adoc)
- [Commits](https://github.com/spring-projects/spring-security/commits)

---
updated-dependencies:
- dependency-name: org.springframework.security:spring-security-bom
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

build.gradle

@@ -114,7 +114,7 @@ ext {
     springGraphqlVersion = '1.3.2'
     springKafkaVersion = '3.3.0-SNAPSHOT'
     springRetryVersion = '2.0.8'
-    springSecurityVersion = '6.4.0-M2'
+    springSecurityVersion = '6.4.0-SNAPSHOT'
     springVersion = '6.2.0-M7'
     springWsVersion = '4.0.11'
     testcontainersVersion = '1.20.1'