build(deps): bump versions.springBootVersion from 2.7.14 to 2.7.15

Bumps `versions.springBootVersion` from 2.7.14 to 2.7.15.

Updates `org.springframework.boot:spring-boot-dependencies` from 2.7.14 to 2.7.15
- [Release notes](https://github.com/spring-projects/spring-boot/releases)
- [Commits](spring-projects/spring-boot@v2.7.14...v2.7.15)

Updates `org.springframework.boot:spring-boot-gradle-plugin` from 2.7.14 to 2.7.15
- [Release notes](https://github.com/spring-projects/spring-boot/releases)
- [Commits](spring-projects/spring-boot@v2.7.14...v2.7.15)

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

Signed-off-by: dependabot[bot] <[email protected]>

dependencies.gradle

@@ -8,7 +8,7 @@ versions.aspectJVersion = "1.9.4"
 versions.apacheDsVersion = "2.0.0.AM26"
 versions.bouncyCastleVersion = "1.76"
 versions.hamcrestVersion = "2.2"
-versions.springBootVersion = "2.7.14"
+versions.springBootVersion = "2.7.15"
 versions.springSecurityJwtVersion = "1.1.1.RELEASE"
 versions.springSecurityOAuthVersion = "2.5.2.RELEASE"
 versions.springSecuritySamlVersion = "1.0.10.RELEASE"