Bump groovyVersion from 3.0.20 to 3.0.21

Bumps `groovyVersion` from 3.0.20 to 3.0.21.

Updates `org.codehaus.groovy:groovy` from 3.0.20 to 3.0.21
- [Commits](https://github.com/apache/groovy/commits)

Updates `org.codehaus.groovy:groovy-xml` from 3.0.20 to 3.0.21
- [Commits](https://github.com/apache/groovy/commits)

---
updated-dependencies:
- dependency-name: org.codehaus.groovy:groovy
  dependency-type: direct:production
  update-type: version-update:semver-patch
- dependency-name: org.codehaus.groovy:groovy-xml
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

build.gradle

@@ -8,7 +8,7 @@ ext {
   assertjVersion = '3.25.3'
   mockitoVersion = '5.10.0'
   pdfTestVersion = '1.8.1'
-  groovyVersion = '3.0.20'
+  groovyVersion = '3.0.21'
   httpclientVersion = '4.5.14'
   restAssuredVersion = '5.4.0'
   junitVersion = '5.10.2'