[groovy] Move def to map for jsonslurper

Author: hazendaz

src/main/groovy/org/codehaus/mojo/spotbugs/SpotBugsMojo.groovy

@@ -1198,7 +1198,7 @@ class SpotBugsMojo extends AbstractMavenReport implements SpotBugsPluginsTrait {
 
         if (sarifTempFile && sarifOutput && sarifTempFile.size() > 0) {
 
-            def slurpedResult = new JsonSlurper().parse(sarifTempFile)
+            Map slurpedResult = new JsonSlurper().parse(sarifTempFile)
             JsonBuilder builder = new JsonBuilder(slurpedResult)
 
             // With -Dspotbugs.sarifFullPath=true