Bump spring.version from 5.3.20 to 5.3.21 in /core

Bumps `spring.version` from 5.3.20 to 5.3.21.

Updates `spring-core` from 5.3.20 to 5.3.21
- [Release notes](https://github.com/spring-projects/spring-framework/releases)
- [Commits](https://github.com/spring-projects/spring-framework/compare/v5.3.20...v5.3.21)

Updates `spring-web` from 5.3.20 to 5.3.21
- [Release notes](https://github.com/spring-projects/spring-framework/releases)
- [Commits](https://github.com/spring-projects/spring-framework/compare/v5.3.20...v5.3.21)

Updates `spring-orm` from 5.3.20 to 5.3.21
- [Release notes](https://github.com/spring-projects/spring-framework/releases)
- [Commits](https://github.com/spring-projects/spring-framework/compare/v5.3.20...v5.3.21)

Updates `spring-jdbc` from 5.3.20 to 5.3.21
- [Release notes](https://github.com/spring-projects/spring-framework/releases)
- [Commits](https://github.com/spring-projects/spring-framework/compare/v5.3.20...v5.3.21)

Updates `spring-tx` from 5.3.20 to 5.3.21
- [Release notes](https://github.com/spring-projects/spring-framework/releases)
- [Commits](https://github.com/spring-projects/spring-framework/compare/v5.3.20...v5.3.21)

Updates `spring-context` from 5.3.20 to 5.3.21
- [Release notes](https://github.com/spring-projects/spring-framework/releases)
- [Commits](https://github.com/spring-projects/spring-framework/compare/v5.3.20...v5.3.21)

Updates `spring-context-support` from 5.3.20 to 5.3.21
- [Release notes](https://github.com/spring-projects/spring-framework/releases)
- [Commits](https://github.com/spring-projects/spring-framework/compare/v5.3.20...v5.3.21)

Updates `spring-test` from 5.3.20 to 5.3.21
- [Release notes](https://github.com/spring-projects/spring-framework/releases)
- [Commits](https://github.com/spring-projects/spring-framework/compare/v5.3.20...v5.3.21)

Updates `spring-aop` from 5.3.20 to 5.3.21
- [Release notes](https://github.com/spring-projects/spring-framework/releases)
- [Commits](https://github.com/spring-projects/spring-framework/compare/v5.3.20...v5.3.21)

Updates `spring-aspects` from 5.3.20 to 5.3.21
- [Release notes](https://github.com/spring-projects/spring-framework/releases)
- [Commits](https://github.com/spring-projects/spring-framework/compare/v5.3.20...v5.3.21)

---
updated-dependencies:
- dependency-name: org.springframework:spring-core
  dependency-type: direct:production
  update-type: version-update:semver-patch
- dependency-name: org.springframework:spring-web
  dependency-type: direct:production
  update-type: version-update:semver-patch
- dependency-name: org.springframework:spring-orm
  dependency-type: direct:production
  update-type: version-update:semver-patch
- dependency-name: org.springframework:spring-jdbc
  dependency-type: direct:production
  update-type: version-update:semver-patch
- dependency-name: org.springframework:spring-tx
  dependency-type: direct:production
  update-type: version-update:semver-patch
- dependency-name: org.springframework:spring-context
  dependency-type: direct:production
  update-type: version-update:semver-patch
- dependency-name: org.springframework:spring-context-support
  dependency-type: direct:production
  update-type: version-update:semver-patch
- dependency-name: org.springframework:spring-test
  dependency-type: direct:production
  update-type: version-update:semver-patch
- dependency-name: org.springframework:spring-aop
  dependency-type: direct:production
  update-type: version-update:semver-patch
- dependency-name: org.springframework:spring-aspects
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

Closes #392

Change-Id: I9a2cd132df58a15555bd1c9507a0eb5333938b3d
diff --git a/core/pom.xml b/core/pom.xml
index 24f3ead..750786b 100644
--- a/core/pom.xml
+++ b/core/pom.xml
@@ -8,7 +8,7 @@
 	<properties>
 		<java.version>1.8</java.version>
 		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
-		<spring.version>5.3.20</spring.version>
+		<spring.version>5.3.21</spring.version>
 		<jersey.version>1.19.4</jersey.version>
 		<jetty.version>9.4.48.v20220622</jetty.version>
 		<hibernate.version>5.6.9.Final</hibernate.version>