(v5.0.x): Bump org.springframework.boot from 4.0.7 to 4.0.8

Bumps [org.springframework.boot](https://github.com/spring-projects/spring-boot) from 4.0.7 to 4.0.8.
- [Release notes](https://github.com/spring-projects/spring-boot/releases)
- [Commits](spring-projects/spring-boot@v4.0.7...v4.0.8)

---
updated-dependencies:
- dependency-name: org.springframework.boot
  dependency-version: 4.0.8
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

gradle/libs.versions.toml

@@ -1,6 +1,6 @@
 [versions]
 javaformat = "0.0.48"
-spring-boot = "4.0.7"
+spring-boot = "4.0.8"
 spring-nohttp = "0.0.11"
 asciidoctor = "4.0.5"
 spring-asciidoctor-backends = "0.0.7"