Bump org.springframework.boot in /getting-started-guides/java (#679)

Bumps [org.springframework.boot](https://github.com/spring-projects/spring-boot) from 3.3.3 to 3.3.4.
- [Release notes](https://github.com/spring-projects/spring-boot/releases)
- [Commits](spring-projects/spring-boot@v3.3.3...v3.3.4)

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

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

getting-started-guides/java/build.gradle

@@ -3,7 +3,7 @@ import org.springframework.boot.gradle.plugin.SpringBootPlugin
 plugins {
   id 'java'
   id 'com.diffplug.spotless' version '6.25.0'
-  id 'org.springframework.boot' version '3.3.3'
+  id 'org.springframework.boot' version '3.3.4'
 }
 
 java {