fix(deps): update dependency org.rundeck:rundeck-core to v5.20.0-20260402

Author: renovate[bot]

gradle/libs.versions.toml

@@ -1,7 +1,7 @@
 [versions]
 axionRelease = "1.18.18"
 groovy = "3.0.24"
-rundeckCore = "5.19.0-20260202"
+rundeckCore = "5.20.0-20260402"
 nexusPublish = "2.0.0"
 spock = "2.3-groovy-3.0"
 # Security overrides for transitive dependencies