[SOLVED] Maven deploy fails with status 422 unprocessable entity

It has been more than a year since I created this question on GitHub Community; a couple of days after that I found the solution by myself, so I answered my own question, and to this date comments keep being added by people who were helped by my post.  

When I look at it today, I notice that my answer has this particular style, this grumpy indignation which has become so characteristic of me, after a lifetime of battling with lame software, and even worse, with lame error messages. 

I thought I should share this on my blog for posterity.

Here is the link:

So the "master" branch is not kosher anymore

The origins of the debate go so far back that they are lost in the mists of time, but a good starting point (which contains references to prior debate) is an Internet Draft from 2018 titled Terminology, Power, and Inclusive Language in Internet-Drafts and RFCs. Some especially woke communities like the Python community had already started applying some of the recommendations in this draft as early as 2019, but things really picked up steam in 2020, with the murder of George Floyd.