chore: bump org.springframework.boot in /dgs-subscription-sse (#3205)

Bumps [org.springframework.boot](https://github.com/spring-projects/spring-boot) from 3.4.2 to 3.4.4.
- [Release notes](https://github.com/spring-projects/spring-boot/releases)
- [Commits](spring-projects/spring-boot@v3.4.2...v3.4.4)

---
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>

Author: dependabot[bot]

dgs-subscription-sse/build.gradle.kts

@@ -2,7 +2,7 @@ import com.netflix.graphql.dgs.codegen.gradle.GenerateJavaTask
 import org.jetbrains.kotlin.gradle.dsl.KotlinVersion
 
 plugins {
-    id("org.springframework.boot") version "3.4.2"
+    id("org.springframework.boot") version "3.4.4"
     id("io.spring.dependency-management") version "1.1.7"
 
     kotlin("jvm") version "2.1.20"