Bump spring-core from 4.1.4.RELEASE to 4.3.21.RELEASE

Bumps [spring-core](https://github.com/spring-projects/spring-framework) from 4.1.4.RELEASE to 4.3.21.RELEASE.
- [Release notes](https://github.com/spring-projects/spring-framework/releases)
- [Commits](spring-projects/spring-framework@v4.1.4.RELEASE...v4.3.21.RELEASE)

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

Author: dependabot[bot]

pom.xml

@@ -20,7 +20,7 @@
 		<dependency>
 			<groupId>org.springframework</groupId>
 			<artifactId>spring-core</artifactId>
-			<version>4.1.4.RELEASE</version>
+			<version>4.3.21.RELEASE</version>
 		</dependency>
 
 		<dependency>