Bump org.springframework:spring-framework-bom from 6.1.20 to 6.1.21 (#10123)

Bumps [org.springframework:spring-framework-bom](https://github.com/spring-projects/spring-framework) from 6.1.20 to 6.1.21.
- [Release notes](https://github.com/spring-projects/spring-framework/releases)
- [Commits](https://github.com/spring-projects/spring-framework/compare/v6.1.20...v6.1.21)

---
updated-dependencies:
- dependency-name: org.springframework:spring-framework-bom
  dependency-version: 6.1.21
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

build.gradle

@@ -115,7 +115,7 @@ ext {
     springKafkaVersion = '3.2.9'
     springRetryVersion = '2.0.12'
     springSecurityVersion = '6.3.9'
-    springVersion = '6.1.20'
+    springVersion = '6.1.21'
     springWsVersion = '4.0.14'
     testcontainersVersion = '1.19.8'
     tomcatVersion = '10.1.42'