Minor changes to the jdk-updates ground rules

[Robert Mckenna]

Hi folks,

Rule 2 of the Ground Rules[0] states that "Changes submitted for a JDK Update repo MUST go through code review, and MUST be approved."

I would like to change that wording to clear up some ambiguity:

"Changes submitted for a JDK Update repo MUST meet the criteria set out in the code review page, and MUST have push approval."

I'll make this edit on Friday the 29th of September unless there are any substantive objections.

    -Rob

[0] https://openjdk.org/projects/jdk-updates/groundrules.html