RFR: Request to backport patches into JFX-11

[Johan Vos]

Hi Kevin,

I ask permission to backport the following issues into 11-dev:

JDK-8231590 <https://bugs.openjdk.java.net/browse/JDK-8231590>: Update
location of jfx repo to GitHub in third-party legal files
JDK-8231854 <https://bugs.openjdk.java.net/browse/JDK-8231854>:  Change
Mercurial to git in various README files
JDK-8218640 <https://bugs.openjdk.java.net/browse/JDK-8218640>: Update
ICU4C to version 64.2
JDK-8232522 <https://bugs.openjdk.java.net/browse/JDK-8232522>: FX: Update
copyright year in docs, readme files to 2020

- Johan