Scala compiler updates

[scala-steward]

About this PR

Updates:

• 📦 org.scala-lang:scala-library from 2.12.20 to 2.12.21
  • 📜 GitHub Release Notes - Version Diff
• 📦 org.scala-lang:scala-library from 2.13.16 to 2.13.18
  • 📜 GitHub Release Notes - Version Diff
• 📦 org.scoverage:sbt-scoverage from 2.3.1 to 2.4.4
  • 📜 GitHub Release Notes - Version Diff

Usage

✅ Please merge!

I'll automatically update this PR to resolve conflicts as long as you don't change it yourself.

If you have any feedback, just mention me in the comments below.

Configure Scala Steward for your repository with a .scala-steward.conf file.

Have a fantastic day writing Scala!

🔍 Files still referring to the old version numbers

The following files still refer to the old version numbers.
You might want to review and update them manually.

build.sbt
project/project/PluginVersions.scala

⚙ Adjust future updates

Add these to your .scala-steward.conf file to ignore future updates of these dependencies:

updates.ignore = [
  { groupId = "org.scala-lang", artifactId = "scala-library" },
  { groupId = "org.scala-lang", artifactId = "scala-library" },
  { groupId = "org.scoverage", artifactId = "sbt-scoverage" }
]

Or, add these to slow down future updates of these dependencies:

dependencyOverrides = [
  {
    pullRequests = { frequency = "30 days" },
    dependency = { groupId = "org.scala-lang", artifactId = "scala-library" }
  },
  {
    pullRequests = { frequency = "30 days" },
    dependency = { groupId = "org.scala-lang", artifactId = "scala-library" }
  },
  {
    pullRequests = { frequency = "30 days" },
    dependency = { groupId = "org.scoverage", artifactId = "sbt-scoverage" }
  }
]

^{labels: library-update, sbt-plugin-update, early-semver-patch, semver-spec-patch, early-semver-minor, semver-spec-minor, old-version-remains, commit-count:n:3}