Prepare release 4.7.0

[cehbrecht]

Overview

This PR prepares the next release v4.7.0.

Related Issue / Discussion

Additional Information

Contribution Agreement

(as per https://github.com/geopython/pywps/blob/master/CONTRIBUTING.rst#contributions-and-licensing)

• I'd like to contribute [feature X|bugfix Y|docs|something else] to PyWPS. I confirm that my contributions to PyWPS will be compatible with the PyWPS license guidelines at the time of contribution.
• I have already previously agreed to the PyWPS Contributions and Licensing Guidelines

[coveralls]

coverage: 84.104%. remained the same
when pulling 6ffe395 on prepare-release-4.7.0
into d4d5574 on main.