Improve the how to contribute document

It would be helpful to have a clarification message on the way a contributor should behave after their commits have got into the dev branch.

“Ideally, when one makes a change that is expected to change the output of the extracted document, they should keep an eye on the integration tests. And maybe “take ownership” (by sending an email to the group saying something like “after my commit X the integration tests started failing, I am looking into it”)”.