Fieldcompare

With this release, `fieldcompare` 0.2.2 is used under the hood, which fixes dependency issues with the new `numpy` 2.0 release.

Minor improvements in the README, in order for better display on the GitHub marketplace.

With this release, we also publish the action on the GitHub Marketplace.

This version of the action uses `fieldcompare` version 0.1.3.

Provides an action around the command-line-interface of `fieldcompare`.