Configuration cache failure when consuming root buildscript `classpath` configuration

[ZacSweers]

When testing dependency guard on CI with configuration cache enabled, it seems to fail on a captured gradle script object. In this case, it's specifically when testing the buildscript classpath itself (literally the classpath configuration on the root project).

Task `:dependencyGuard` of type `com.dropbox.gradle.plugins.dependencyguard.internal.list.DependencyGuardListTask`: cannot serialize Gradle script object references as these are not supported with the configuration cache.

This is with 0.5.0

[ZacSweers]

Here's the report from Gradle

[ZacSweers]

And here's our DSL usage. Note the issue persists even if I completely remove the trailing configuration block, so it's not an issue of that block capturing something by accident

dependencyGuard {
  configuration("classpath") {
    baselineMap = { dependencyName: String ->
      if (".gradle.plugin:" in dependencyName) {
        // Ignore gradle plugin markers, they're redundant for this case and just noise
        null
      } else {
        dependencyName
      }
    }
  }
}