3.3.x: Bump org.springframework.boot:spring-boot-dependencies

Bumps [org.springframework.boot:spring-boot-dependencies](https://github.com/spring-projects/spring-boot) from 3.3.4 to 3.3.9.
- [Release notes](https://github.com/spring-projects/spring-boot/releases)
- [Commits](https://github.com/spring-projects/spring-boot/compare/v3.3.4...v3.3.9)

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

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

build.gradle

@@ -23,7 +23,7 @@ plugins {
 description = "Spring CredHub"
 
 ext {
-	springBootVersion = "3.3.4"
+	springBootVersion = "3.3.9"
 	javadocLinks = [
 			"https://docs.oracle.com/en/java/javase/17/docs/api/",
 			"https://docs.spring.io/spring-framework/docs/current/javadoc-api/"