Update scala-xml to 2.1.0

[scala-steward]

Updates org.scala-lang.modules:scala-xml from 1.3.0 to 2.1.0. GitHub Release Notes - Version Diff

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

If you'd like to skip this version, you can just close this PR. 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!

Adjust future updates

Add this to your `.scala-steward.conf` file to ignore future updates of this dependency: ``` updates.ignore = [ { groupId = "org.scala-lang.modules", artifactId = "scala-xml" } ] ``` Or, add this to slow down future updates of this dependency: ``` dependencyOverrides = [{ pullRequest = { frequency = "@monthly" }, dependency = { groupId = "org.scala-lang.modules", artifactId = "scala-xml" } }] ```

labels: library-update, early-semver-major, semver-spec-major, commit-count:1

[sjenna]

Closed because the purpose of this repo is to set the version where it is. I will make a PR to add the scala steward config.