RFR: JDK-8203497: Bump Jib format version to 1.2

[Erik Joelsson]

The jib format version is defined in jib-profiles.js. It is used by Jib 
to identify correct parsing of the file and adjust behavior of Jib if 
necessary. This version needs to be bumped to 1.2.

Bug: https://bugs.openjdk.java.net/browse/JDK-8203497
Webrev: http://cr.openjdk.java.net/~erikj/8203497/webrev.01/

/Erik