hg: openjfx/12-dev/rt: 8228422: change release version to 12.0.2

[johan at lodgon.com]

Changeset: a7030a84bc21
Author:    jvos
Date:      2019-07-19 15:04 +0200
URL:       https://hg.openjdk.java.net/openjfx/12-dev/rt/rev/a7030a84bc21

8228422: change release version to 12.0.2
Reviewed-by: kcr

! build.properties