Bump azure-spring-boot-bom from 3.14.0 to 4.0.0

Bumps [azure-spring-boot-bom](https://github.com/Azure/azure-sdk-for-java) from 3.14.0 to 4.0.0.
- [Release notes](https://github.com/Azure/azure-sdk-for-java/releases)
- [Changelog](https://github.com/Azure/azure-sdk-for-java/blob/v4.0.0/changelog.md)
- [Commits](Azure/azure-sdk-for-java@azure-spring-boot_3.14.0...v4.0.0)

---
updated-dependencies:
- dependency-name: com.azure.spring:azure-spring-boot-bom
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

spring-cloud-config-azure-keyvault-starter/pom.xml

@@ -58,7 +58,7 @@
         <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
         <java.version>1.8</java.version>
         <spring-cloud.version>2021.0.0</spring-cloud.version>
-        <azure.spring-boot.version>3.14.0</azure.spring-boot.version>
+        <azure.spring-boot.version>4.0.0</azure.spring-boot.version>
     </properties>
 
     <dependencies>