feat(sbt): Support private variable version resolving

[yamachu]

ref: #3827

Thanks to #3828 , I could update scala packages automatically.

In my use case, I make private variable which shows package version.

For example

Dependencies.scala

object Dependencies
{
  private val somePackageVersion = "1.2.3"
  private val anotherPackageVersion = "2.3.4"
  
  private val somePackage = "foo" % "bar" % somePackageVersion
  private val anotherPackage = "buz" % "piyo" % anotherPackageVersion

  lazy val myAwesomeLibraryDependencies = Seq(somePackage, anotherPackage)
}

build.sbt

~...

libraryDependencies ++= myAwesomeLibraryDependencies

If renovate supports private variable, it would be able to parse this structure.

[zharinov]

Thanks @yamachu, looks good to me

[viceice]

The regex should be constant in module scope.

[rarkins]

@viceice is that related to this PR specifically, or something should be refactored before or after?

[renovate-release]

🎉 This PR is included in version 21.15.0 🎉

The release is available on:

• GitHub release
• 21.15.0

Your semantic-release bot 📦🚀

[yamachu]

Thanks!

[rarkins]

@yamachu thank you!