Add Scala 3

[steinybot]

No description provided.

[sjrd]

Thank you for your interest. However this is not an improvement for this library, so I will close the PR.

As a JDK extension for Scala.js, there is a unique artifact for 2.13 and 3, built with 2.13. It can/must be used from Scala 3 with a cross(CrossVersion.for3Use2_13), as mentioned in the readme. If we publish both a _2.13 and a _3 artifact, we break transitive dependents.

Btw, you most likely should not use this library at all. Use https://github.com/scala-js/scala-js-java-securerandom instead.

[steinybot]

Appoligies, I was updating an old repo. I didn't notice that cross version at the end (it is off the screen in my browser).