jfx20u now open for JavaFX 20.0.2 backports

[Kevin Rushforth]

All,

The jfx20u repo is now open for JavaFX 20.0.2 backports, with prior 
approval. The general criteria is that we want to backport fixes for 
regressions introduced in JavaFX 20, third-party library updates, and a 
limited number of other important bug fixes. In most cases we'd like to 
see the fix "bake" in the mainline for a while before being backported 
to jfx20u.

To make the process of tracking the request and approval easier, we 
would like to adopt a similar procedure for making the request and 
noting the approval as is used by the JDK updates releases -- by using 
JBS labels to request a backport and indicate approval or rejection.

Here is the procedure:

1. A developer makes the request by adding the "jfx20u-fix-request" 
label to the main bug in JBS (not the backport record, even presuming 
one exists), with a comment indicating that you would like to backport 
it, along with a justification and risk assessment.

2. One of the JavaFX projects leads, either Johan Vos or myself, will 
add a "jfx20u-fix-yes" label to approve or "jfx20u-fix-no" label to 
reject the request, along with a comment. In either case, the 
jfx20u-request label is left in place.

3. Once the bug has the "jfx20u-fix-yes" label, you can create the 
backport PR for jfx20u.

Let Johan or me know if you have any questions.

Thanks.

-- Kevin