Add Scala CLA to the Allowlist

[JD557]

Add the Scala CLA to the Allowlist.
We need to sign this CLA to be able to contribute with fixes to the Scala compiler and some of the official libraries and plugins.

Some relevant projects under this CLA:

• Scala compiler: https://github.com/scala/scala
• Dotty compiler: https://github.com/lampepfl/dotty
• Scala-XML: https://github.com/scala/scala-xml
• Scala-JS: https://github.com/scala-js/scala-js
• Scala-Native: https://github.com/scala-native/scala-native