Update Gretty to 2.3.1

Fixes gh-7389

gradle/dependency-management.gradle

@@ -98,10 +98,10 @@ dependencyManagement {
 		dependency 'nz.net.ultraq.thymeleaf:thymeleaf-expression-processor:1.1.3'
 		dependency 'nz.net.ultraq.thymeleaf:thymeleaf-layout-dialect:2.4.1'
 		dependency 'ognl:ognl:3.1.12'
-		dependency 'org.akhikhl.gretty:gretty-runner-tomcat9:2.3.0'
-		dependency 'org.akhikhl.gretty:gretty-runner-tomcat:2.3.0'
-		dependency 'org.akhikhl.gretty:gretty-runner:2.3.0'
-		dependency 'org.akhikhl.gretty:gretty-runner:2.3.0'
+		dependency 'org.akhikhl.gretty:gretty-runner-tomcat9:2.3.1'
+		dependency 'org.akhikhl.gretty:gretty-runner-tomcat:2.3.1'
+		dependency 'org.akhikhl.gretty:gretty-runner:2.3.1'
+		dependency 'org.akhikhl.gretty:gretty-runner:2.3.1'
 		dependency 'org.apache.commons:commons-collections4:4.1'
 		dependency 'org.apache.commons:commons-exec:1.3'
 		dependency 'org.apache.commons:commons-lang3:3.7'