[Build] Fix publish.gradle script

publish.gradle

@@ -63,7 +63,7 @@ ext.configurePublishing = { packageName, packageDesc, packageVersion ->
             def signingKeyId = System.getenv('SIGNING_KEY_ID')
             def signingKey = System.getenv('SIGNING_KEY')
             useInMemoryPgpKeys(signingKeyId, signingKey, '')
-            sign publishing.publications.mavenJava
+            sign publishing.publications.imgui
         }
     }
 }