fix(dg/koji): add flowchart for precheck

[mfocko]

Add flowchart that should be explicit about the way Packit decides whether to run or skip Koji build when a dist-git event is registered.

Fixes #826

[softwarefactory-project-zuul[bot]]

Build succeeded. https://softwarefactory-project.io/zuul/t/packit-service/buildset/28bdd6b01f3740d0a13d9ecebe093deb

:heavy_check_mark: pre-commit SUCCESS in 1m 11s

[mfocko]

thanks, it is much clearer from this!

But the specfile change is checked in both cases (just that currently, for pushes this pre-filtering is already done in fedmsg listener)

I think I can simplify it with that… also adding the comment trigger

[softwarefactory-project-zuul[bot]]

Build failed. https://softwarefactory-project.io/zuul/t/packit-service/buildset/d1b843c16aeb49e8967b185cb639a83a

:x: pre-commit FAILURE in 1m 23s

[softwarefactory-project-zuul[bot]]

Build failed. https://softwarefactory-project.io/zuul/t/packit-service/buildset/3de5a2ff11e74011a7f8451b115d4339

:x: pre-commit FAILURE in 1m 17s

[softwarefactory-project-zuul[bot]]

Build succeeded. https://softwarefactory-project.io/zuul/t/packit-service/buildset/6b9e3995e3f24f57adbf9a5622f341dc

:heavy_check_mark: pre-commit SUCCESS in 1m 11s

[softwarefactory-project-zuul[bot]]

Build succeeded (gate pipeline). https://softwarefactory-project.io/zuul/t/packit-service/buildset/07904f3cdb054068b5451876d254511e

:heavy_check_mark: pre-commit SUCCESS in 1m 11s