ratchetFrom broken when using git worktrees

[devinrsmith]

A colleague of mine, @nbauernfeind, ran into an issue running ./gradlew spotlessApply. After a bit of debugging, we isolated it to using ratchetFrom in combination with a git worktree. It's a relatively easy issue to workaround (just use a plain git clone instead of worktree); but posting here in case anybody else runs into it until it can be fixed.

Caused by: java.lang.IllegalArgumentException: Cannot find git repository in any parent directory
        at com.diffplug.spotless.extra.GitRatchet.repositoryFor(GitRatchet.java:156)
        at com.diffplug.spotless.extra.GitRatchet.repositoryFor(GitRatchet.java:161)
        at com.diffplug.spotless.extra.GitRatchet.repositoryFor(GitRatchet.java:161)
        at com.diffplug.spotless.extra.GitRatchet.rootTreeShaOf(GitRatchet.java:226)
        at com.diffplug.gradle.spotless.SpotlessTask.setupRatchet(SpotlessTask.java:91)
        at com.diffplug.gradle.spotless.FormatExtension.setupTask(FormatExtension.java:733)
        at com.diffplug.gradle.spotless.JavaExtension.setupTask(JavaExtension.java:164)
        at com.diffplug.gradle.spotless.SpotlessExtensionImpl.lambda$createFormatTasks$6(SpotlessExtensionImpl.java:84)

Version: 5.14.2

[nedtwigg]

Dupe of #75