Bump org.springframework.boot:spring-boot-starter (#3763)

Bumps the development-dependencies group with 1 update: [org.springframework.boot:spring-boot-starter](https://github.com/spring-projects/spring-boot).


Updates `org.springframework.boot:spring-boot-starter` from 3.3.8 to 3.3.9
- [Release notes](https://github.com/spring-projects/spring-boot/releases)
- [Commits](https://github.com/spring-projects/spring-boot/compare/v3.3.8...v3.3.9)

---
updated-dependencies:
- dependency-name: org.springframework.boot:spring-boot-starter
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: development-dependencies
...

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

build.gradle

@@ -67,7 +67,7 @@ ext {
 	mockitoVersion = '5.14.2'
 	reactorVersion = '2024.0.3'
 	scalaVersion = '2.13'
-	springBootVersion = '3.3.8' // docs module
+	springBootVersion = '3.3.9' // docs module
 	springDataVersion = '2024.1.3'
 	springRetryVersion = '2.0.11'
 	springVersion = '6.2.3'