Update to hsqldb:2.3.6

Fixes gh-5810

gradle/javaprojects.gradle

@@ -18,7 +18,7 @@ ext.commonsLoggingVersion = '1.2'
 ext.ehcacheVersion = '2.10.5'
 ext.gebVersion = '0.10.0'
 ext.groovyVersion = '2.4.4'
-ext.hsqlVersion = '2.3.2'
+ext.hsqlVersion = '2.3.6'
 ext.hibernateVersion = '5.0.12.Final'
 ext.hibernateValidatorVersion = '5.3.6.Final'
 ext.jacksonDatabindVersion = '2.8.11.1'