Use the cfg.jdk for scala-cli

[rossabaker]

See #84.

[rossabaker]

This works great on the application shell:

> nix develop .#application
🔨 Welcome to typelevel-app-shell

[general commands]

  menu      - prints this menu
  metals    - Work-in-progress language server for Scala
  sbt       - A build tool for Scala, Java and more
  scala-cli - Command-line tool to interact with the Scala language

[versions]

  Java - 17.0.3

[typelevel-app-shell]$ scala-cli 
Welcome to Scala 3.2.1 (17.0.3, Java OpenJDK 64-Bit Server VM).
Type in expressions for evaluation. Or try :

But not on the library shell:

$ nix develop .#library
error: scala-cli requires Java 17 or newer, but zulu8.54.0.21-ca-jdk-8.0.292 is 8.0.292

It's nice if they line up in the application shell, but they can't in the library shell.