Bump build-plugins from 2025.2 to 2025.6

Bumps `build-plugins` from 2025.2 to 2025.6.

Updates `io.openapiprocessor:build-plugins` from 2025.2 to 2025.6

Updates `io.openapiprocessor.build.plugin.publish-central` from 2025.2 to 2025.6

---
updated-dependencies:
- dependency-name: io.openapiprocessor:build-plugins
  dependency-version: '2025.6'
  dependency-type: direct:production
  update-type: version-update:semver-minor
- dependency-name: io.openapiprocessor.build.plugin.publish-central
  dependency-version: '2025.6'
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

gradle/libs.versions.toml

@@ -7,7 +7,7 @@ kotlin = "2.2.10"
 build-jdk = "11"
 #target-jdk = "11"
 test-jdk = "17"
-build-plugins = "2025.2"
+build-plugins = "2025.6"
 
 junit = "5.13.4"
 jacoco = "0.8.13"