chore(deps): bump com.sap.cloud.sdk:sdk-bom from 5.20.0 to 5.21.0

Bumps [com.sap.cloud.sdk:sdk-bom](https://github.com/SAP/cloud-sdk-java) from 5.20.0 to 5.21.0.
- [Release notes](https://github.com/SAP/cloud-sdk-java/releases)
- [Changelog](https://github.com/SAP/cloud-sdk-java/blob/main/release_notes.md)
- [Commits](SAP/cloud-sdk-java@rel/5.20.0...rel/5.21.0)

---
updated-dependencies:
- dependency-name: com.sap.cloud.sdk:sdk-bom
  dependency-version: 5.21.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

pom.xml

@@ -35,7 +35,7 @@
     <junit-jupiter.version>5.13.4</junit-jupiter.version>
     <assertj.version>3.27.3</assertj.version>
     <mockito.version>5.18.0</mockito.version>
-    <sdk-bom.version>5.20.0</sdk-bom.version>
+    <sdk-bom.version>5.21.0</sdk-bom.version>
     <mockito-bom.version>5.18.0</mockito-bom.version>
     <bcpkix-jdk18on.version>1.81</bcpkix-jdk18on.version>
   </properties>