Bump springBootVersion from 3.3.5 to 3.4.0

Bumps `springBootVersion` from 3.3.5 to 3.4.0.

Updates `org.springframework.boot:spring-boot-gradle-plugin` from 3.3.5 to 3.4.0
- [Release notes](https://github.com/spring-projects/spring-boot/releases)
- [Commits](spring-projects/spring-boot@v3.3.5...v3.4.0)

Updates `org.springframework.boot:spring-boot-starter-web` from 3.3.5 to 3.4.0
- [Release notes](https://github.com/spring-projects/spring-boot/releases)
- [Commits](spring-projects/spring-boot@v3.3.5...v3.4.0)

Updates `org.springframework.boot:spring-boot-starter-thymeleaf` from 3.3.5 to 3.4.0
- [Release notes](https://github.com/spring-projects/spring-boot/releases)
- [Commits](spring-projects/spring-boot@v3.3.5...v3.4.0)

Updates `org.springframework.boot:spring-boot-starter-test` from 3.3.5 to 3.4.0
- [Release notes](https://github.com/spring-projects/spring-boot/releases)
- [Commits](spring-projects/spring-boot@v3.3.5...v3.4.0)

Updates `org.springframework.boot:spring-boot-configuration-processor` from 3.3.5 to 3.4.0
- [Release notes](https://github.com/spring-projects/spring-boot/releases)
- [Commits](spring-projects/spring-boot@v3.3.5...v3.4.0)

---
updated-dependencies:
- dependency-name: org.springframework.boot:spring-boot-gradle-plugin
  dependency-type: direct:production
  update-type: version-update:semver-minor
- dependency-name: org.springframework.boot:spring-boot-starter-web
  dependency-type: direct:production
  update-type: version-update:semver-minor
- dependency-name: org.springframework.boot:spring-boot-starter-thymeleaf
  dependency-type: direct:production
  update-type: version-update:semver-minor
- dependency-name: org.springframework.boot:spring-boot-starter-test
  dependency-type: direct:production
  update-type: version-update:semver-minor
- dependency-name: org.springframework.boot:spring-boot-configuration-processor
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

build.gradle

@@ -1,6 +1,6 @@
 buildscript {
     ext {
-        springBootVersion = '3.3.5'
+        springBootVersion = '3.4.0'
         springVersion = '6.1.12'
         tomcatVersion = '10.1.34'
         seleniumVersion = '4.27.0'