[11u] RFR: 8257580: Bump update version for OpenJDK: jdk-11.0.12

[Lindenmaier, Goetz]

Hi,

Next week 11.0.12 development will start in jdk11u-dev.
We need to bump the version.  Please review.
See also https://wiki.openjdk.java.net/display/JDKUpdates/JDK11u

Please review:
http://cr.openjdk.java.net/~goetz/wr21/8257580-version_11.0.12-jdk11/01/

Best regards,
  Goetz.