Write out JaCoCo coverage report to build folder (#993)

According to the SonarQube docs this will then get picked up by
the sonar gradle plugin, providing coverage information within
SonarQube Cloud

service/build.gradle

@@ -82,6 +82,9 @@ test {
 }
 
 jacocoTestReport {
+	reports {
+		xml.required = true
+	}
 	dependsOn test // tests are required to run before generating the report
 }