Update Spring Boot version references from 3.5.6 to 4.0.5

Agent-Logs-Url: https://github.com/rashidi/spring-boot-tutorials/sessions/f10a6385-b245-4d50-9e5e-9b44ec077d15

Co-authored-by: rashidi <380073+rashidi@users.noreply.github.com>

Author: Copilot

README.adoc

@@ -9,7 +9,7 @@ Spring Data, Spring Batch, Spring Cloud, Spring Security, Spring GraphQL, and Sp
 with source code in individual submodules and can be found on {url-quickref}[GitHub].
 
 image:https://img.shields.io/badge/Java_-25-blue?style=flat-square[Static Badge]
-image:https://img.shields.io/badge/Spring_Boot-3.5.6-blue?style=flat-square&logo=springboot[Spring Boot version]
+image:https://img.shields.io/badge/Spring_Boot-4.0.5-blue?style=flat-square&logo=springboot[Spring Boot version]
 image:https://img.shields.io/github/actions/workflow/status/rashidi/spring-boot-tutorials/gradle-build.yml?style=flat-square&logo=githubactions&color=blue[Gradle Build]
 image:https://img.shields.io/github/actions/workflow/status/rashidi/spring-boot-tutorials/build-and-publish-antora.yml?style=flat-square&logo=antora&label=Antora&color=blue[Antora Site Status, link={url-docs}]
 image:https://img.shields.io/sonar/coverage/rashidi_spring-boot-tutorials?server=https%3A%2F%2Fsonarcloud.io&style=flat-square&color=blue[Sonar Coverage]
@@ -28,7 +28,7 @@ and always will be, my primary goal.
 
 With the help of https://github.com/dependabot[Dependabot], each tutorial is also kept up-to-date with the latest
 dependencies. Currently, we are using Java https://adoptium.net/en-GB/temurin/releases?version=25[Temurin 25]
-with https://plugins.gradle.org/plugin/org.springframework.boot/3.5.6[Spring Boot 3.5.6].
+with https://plugins.gradle.org/plugin/org.springframework.boot/4.0.5[Spring Boot 4.0.5].
 
 == Documentation
 

supplemental-ui/partials/footer-content.hbs

@@ -2,6 +2,6 @@
     <p>Spring Boot Tutorials by <a href="https://about.me/rashidi.zin">Rashidi Zin</a></p>
     <p id="badges">
         <img alt="Java version" src="https://img.shields.io/badge/Java_-25-blue?style=flat-square" />
-        <img alt="Spring Boot version" src="https://img.shields.io/badge/Spring_Boot-3.5.6-blue?style=flat-square&logo=springboot" />
+        <img alt="Spring Boot version" src="https://img.shields.io/badge/Spring_Boot-4.0.5-blue?style=flat-square&logo=springboot" />
         <img alt="License - Unlicense" src="https://img.shields.io/github/license/rashidi/spring-boot-tutorials?style=flat-square&color=blue" />
 </footer>