Add Central Portal Snapshots repository for rundeck-core:6.0.0-SNAPSHOT resolution

- Required for local builds and JitPack
- Resolves org.rundeck dependencies from Central Portal (OSSRH sunset)

Author: fdevans

build.gradle

@@ -28,6 +28,13 @@ project.version = '1.3.18-grails7-upgrade-test'
 
 repositories {
     mavenLocal()
+    maven {
+        name = 'Central Portal Snapshots'
+        url = 'https://central.sonatype.com/repository/maven-snapshots/'
+        content {
+            includeGroup('org.rundeck')
+        }
+    }
     maven {
         name = 'Central Portal Snapshots'
         url = 'https://central.sonatype.com/repository/maven-snapshots/'