RFR: JDK-8222839 : increase security version for 12-dev

[Johan Vos]

Hi Kevin,

Please review https://bugs.openjdk.java.net/browse/JDK-8228422 with webrev
at http://cr.openjdk.java.net/~jvos/8228422/webrev.00/ which increases the
security version in the 12-dev repository.

Thanks,

- Johan