Proposed schedule for JavaFX 19

[Kevin Rushforth]

Here is the proposed schedule for JavaFX 19.

RDP1: Jul 14, 2022 (aka “feature freeze”)
RDP2: Aug 4, 2022
Freeze: Aug 25, 2022
GA: Sep 13, 2022

We plan to fork a jfx19 stabilization branch at RDP1. The GA date is one 
week ahead of JDK 19, matching what we did for 18.

The start of RDP1, the start of RDP2, and the code freeze will be 16:00 
UTC on the respective dates.

Please let Johan or me know if you have any questions.

-- Kevin