build(deps): bump org.jreleaser from 1.18.0 to 1.21.0

Bumps org.jreleaser from 1.18.0 to 1.21.0.

---
updated-dependencies:
- dependency-name: org.jreleaser
  dependency-version: 1.21.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

build.gradle

@@ -1,7 +1,7 @@
 plugins {
   id 'java-library'
   id 'maven-publish'
-  id 'org.jreleaser' version '1.18.0'
+  id 'org.jreleaser' version '1.21.0'
   id "com.diffplug.spotless" version "6.13.0"
 }