Update specs2-core to 4.20.9

[scala-steward]

About this PR

📦 Updates org.specs2:specs2-core from 4.17.0 to 4.20.9

Usage

✅ Please merge!

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.

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⚙ Adjust future updates

Add this to your `.scala-steward.conf` file to ignore future updates of this dependency: ``` updates.ignore = [ { groupId = "org.specs2", artifactId = "specs2-core" } ] ``` Or, add this to slow down future updates of this dependency: ``` dependencyOverrides = [{ pullRequests = { frequency = "30 days" }, dependency = { groupId = "org.specs2", artifactId = "specs2-core" } }] ```

^{labels: test-library-update, early-semver-minor, semver-spec-minor, version-scheme:semver-spec, commit-count:1}