Document sbt support for dependency scanning

changelogs/unreleased/12390-document-sbt-support.yml

+---
+title: Document support for sbt dependency scanning
+merge_request: 21588
+author:
+type: added

doc/user/application_security/dependency_scanning/index.md

@@ -64,6 +64,7 @@ The following languages and dependency managers are supported.
 | Python ([Pipfile](https://pipenv.kennethreitz.org/en/latest/basics/)) | not currently ([issue](https://gitlab.com/gitlab-org/gitlab/issues/11756 "Pipfile.lock support for Dependency Scanning"))| not available |
 | Python ([poetry](https://poetry.eustace.io/)) | not currently ([issue](https://gitlab.com/gitlab-org/gitlab/issues/7006 "Support Poetry in Dependency Scanning")) | not available |
 | Ruby ([gem](https://rubygems.org/)) | yes | [gemnasium](https://gitlab.com/gitlab-org/security-products/gemnasium), [bundler-audit](https://github.com/rubysec/bundler-audit) |
+| Scala ([sbt](https://www.scala-sbt.org/)) | yes | [gemnasium](https://gitlab.com/gitlab-org/security-products/gemnasium) |
 
 ## Configuration