Add an action which reports the changes of the fields by a PR

[dachengx]

To prevent the issue in #1247 convert some cs2_area_fraction_top to nans) from happening again(at least prevent it from happening a lot), we should check the impact of one PR on the fields.

In details, we should check

1. The change in the number of nans.
2. The deleted or added fields.

These can be done by writing scripts of actions.

[dachengx]

Assuming that we have some functions to iterate through the dependency tree and order the plugins by their "genetic relationship", then we can search for the oldest change of lineage, and compare the data produced.

Here is the plan:

1. search for deleted plugins, and report their names
2. search for the added plugins and report:
   +. the fraction of nan(0 and -1) of float(int) fields
3. search for the oldest changed(in lineage, because the __version__ will be tracked by lineage) plugin and report
   +. the fraction of nan(0 and -1) of float(int) fields
   +. the mean absolute change in each field
   +. whether the oldest lineage-changed plugin is really the oldest results-changed plugin by comparing the result of the second oldest layer of plugins
4. if possible, compare the change codes, hint at which plugin is really changed by programmer

[JYangQi00]

Thanks Dacheng, is there a database somewhere which tracks the lineage hash of the previous version of plugins, so that we can compare it to the lineage hash of the plugins of a PR?

[dachengx]

The lineage must be deduced from the given codes and configs. So no such docs.