DAST moved to a monthly updated instead of a weekly one

Summary

Before 11.9, DAST job definition was directly using the weekly ZAProxy docker image. When vendoring our job definition we also switched to our own wrapper project instead, which is a monthly updated image.

What is the current bug behavior?

DAST image is updated monthly (when releasing the x-y-stable docker image).

What is the expected correct behavior?

DAST image is updated weekly to integrate the weekly update of ZAProxy.

Possible fixes

Temporary workaround: Manually rebuilding the image on a weekly basis. This can be done by re-running a pipeline for the last tagged release (v1.2.1 as of June 3rd, 2019)

Real fix: Update the release process and CI config to automatically rebuild the x-y-stable images on a weekly basis.