[13u] RFR: 8241913: Bump update version for OpenJDK: jdk-13.0.4

[Yuri Nesterenko]

Hi,

to start the next development period of jdk-13.0.4, we need to bump the version in jdk13u-dev
Please review:
http://cr.openjdk.java.net/~yan/8241913/webrev.0/

I'll push the change after successful request to add 13.0.4 to JBS and to hgupdater.

Release date set to July 14, see https://www.oracle.com/security-alerts/

Thanks,
--yan