Scanning dependencies for this library I see the following vulnerability being raised for System.Text.RegularExpressions 4.3.0, which is a transitive dependency within Sprache 2.3.1.
To resolve this, it would be good to move away from Sprache 2.3.1 (I believe there is a prerelease of 3.0.0 that addresses this)
Further Info:
dotnet/announcements#111