Add feature overview to the README

[fthomas]

[fthomas]

Here are some features off the top of my head:

• supported build tools:

  • sbt
  • Mill
  • Maven

• supported software forges:

  • GitHub
  • GitLab
  • Bitbucket
  • Bitbucket Server
  • Azure Repos

• Scalafix migrations (post and pre update)

• artifact migrations (renaming of groupId and artifactId)

• post-update hooks

• configuration

  • pinning, ignoring
  • scheduling updates (schedules per dependency)
  • grouping updates

• multiple branches

• scalafmt

  • git-ignore-blame-revs

(I probably missed some really important ones :-)