Bump spring-boot-dependencies from 2.4.2 to 2.4.3 in /java/backend (#192

)

Bumps [spring-boot-dependencies](https://github.com/spring-projects/spring-boot) from 2.4.2 to 2.4.3.
- [Release notes](https://github.com/spring-projects/spring-boot/releases)
- [Commits](spring-projects/spring-boot@v2.4.2...v2.4.3)

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

java/backend/build.gradle

@@ -8,7 +8,7 @@ plugins {
 
 group = 'uk.gov.hmcts.ccf'
 version = '0.0.1-SNAPSHOT'
-def springBootVersion = '2.4.2'
+def springBootVersion = '2.4.3'
 
 repositories {
     jcenter()