fix: compile error

Author: jpedroh

src/main/services/dataCollectors/GenericMerge/GenericMergeDataCollector.groovy

@@ -28,7 +28,7 @@ class GenericMergeDataCollector implements DataCollector {
         def scenarios = MergeScenarioCollector.collectMergeScenarios(project, mergeCommit)
                 .parallelStream()
                 .filter(NonFastForwardMergeScenarioFilter::isNonFastForwardMergeScenario)
-                .collect(Collectors.toUnmodifiableList())
+                .collect(Collectors.toList())
         LOG.trace("Finished filtering of files to exclude fast forwards")
 
         LOG.trace("Starting normalization of merge files on scenario")