Bump org.springframework.boot from 2.6.7 to 3.1.3 in /shows-dgs

Bumps [org.springframework.boot](https://github.com/spring-projects/spring-boot) from 2.6.7 to 3.1.3.
- [Release notes](https://github.com/spring-projects/spring-boot/releases)
- [Commits](spring-projects/spring-boot@v2.6.7...v3.1.3)

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

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

shows-dgs/build.gradle.kts

@@ -17,7 +17,7 @@
 import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
 
 plugins {
-	id("org.springframework.boot") version "2.6.7"
+	id("org.springframework.boot") version "3.1.3"
 	id("io.spring.dependency-management") version "1.0.12.RELEASE"
 	kotlin("jvm") version "1.7.10"
 	kotlin("plugin.spring") version "1.6.21"