[jfx20] RFR: 8304359: Create release notes for JavaFX 20 [v5]

[Johan Vos]

On Fri, 17 Mar 2023 16:47:11 GMT, Kevin Rushforth <kcr at openjdk.org> wrote:

>> Release notes for JavaFX 20, including one important change to note (the requirement of JDK 17 as the minimum needed to run JavaFX 20) and the list of enhancements and bugs fixed in this release.
>> 
>> Note: This PR is targeted to `jfx20`.
>
> Kevin Rushforth has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Change whitespace to match prior releases: ' | ' -> '|'

Marked as reviewed by jvos (Reviewer).

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PR: https://git.openjdk.org/jfx/pull/1060