Bump kiwi-bom from 0.20.0 to 0.21.0 (#144)

Bumps [kiwi-bom](https://github.com/kiwiproject/kiwi-bom) from 0.20.0 to 0.21.0.
- [Release notes](https://github.com/kiwiproject/kiwi-bom/releases)
- [Commits](kiwiproject/kiwi-bom@v0.20.0...v0.21.0)

---
updated-dependencies:
- dependency-name: org.kiwiproject:kiwi-bom
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

pom.xml

@@ -46,7 +46,7 @@
 
     <properties>
 
-        <kiwi-bom.version>0.20.0</kiwi-bom.version>
+        <kiwi-bom.version>0.21.0</kiwi-bom.version>
 
         <!-- Sonar properties -->
         <sonar.projectKey>kiwiproject_retrying-again</sonar.projectKey>