Bump springboot.version from 3.5.6 to 4.0.0

Bumps `springboot.version` from 3.5.6 to 4.0.0.

Updates `org.springframework.boot:spring-boot-dependencies` from 3.5.6 to 4.0.0
- [Release notes](https://github.com/spring-projects/spring-boot/releases)
- [Commits](spring-projects/spring-boot@v3.5.6...v4.0.0)

Updates `org.springframework.boot:spring-boot-maven-plugin` from 3.5.6 to 4.0.0
- [Release notes](https://github.com/spring-projects/spring-boot/releases)
- [Commits](spring-projects/spring-boot@v3.5.6...v4.0.0)

---
updated-dependencies:
- dependency-name: org.springframework.boot:spring-boot-dependencies
  dependency-version: 4.0.0
  dependency-type: direct:production
  update-type: version-update:semver-major
- dependency-name: org.springframework.boot:spring-boot-maven-plugin
  dependency-version: 4.0.0
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

examples/spring-web/pom.xml

@@ -17,7 +17,7 @@
 
   <properties>
     <maven.compiler.release>17</maven.compiler.release>
-    <springboot.version>3.5.6</springboot.version>
+    <springboot.version>4.0.0</springboot.version>
   </properties>
 
   <dependencyManagement>

examples/springboot/pom.xml

@@ -17,7 +17,7 @@
 
   <properties>
     <maven.compiler.release>17</maven.compiler.release>
-    <springboot.version>3.5.6</springboot.version>
+    <springboot.version>4.0.0</springboot.version>
   </properties>
 
   <dependencyManagement>