Bump eu.maveniverse.maven.parent:parent from 20 to 21 (#138)

Bumps [eu.maveniverse.maven.parent:parent](https://github.com/maveniverse/parent) from 20 to 21.
- [Release notes](https://github.com/maveniverse/parent/releases)
- [Commits](https://github.com/maveniverse/parent/commits)

---
updated-dependencies:
- dependency-name: eu.maveniverse.maven.parent:parent
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

pom.xml

@@ -14,7 +14,7 @@
   <parent>
     <groupId>eu.maveniverse.maven.parent</groupId>
     <artifactId>parent</artifactId>
-    <version>20</version>
+    <version>21</version>
   </parent>
 
   <groupId>eu.maveniverse.maven.toolbox</groupId>