[Announcement] Switch Azul Open JDK to Adopt Open JDK #1057

Hello,
Currently, we install Azul Open JDK to our images.
We are going to switch to Adopt Open JDK on all images (Windows, Ubuntu, macOS) in a few weeks.
We don't expect any impact because these distributions are pretty similar but Adopt Open JDK is more free from the license side.

Notes:

1. Java 7 will continue to use Azul Open JDK because Adopt Open JDK doesn't provide Java 7 support
2. We are going to remove Java 12 on Ubuntu 20.