packagekit: Update the severity colors to more a11y friendly ones
packagekit: Update the severity colors to more a11y friendly ones

The guidelines from UXD was updated, since the old colors had some
some visibility issues for people with a certain color blindness.

Fixes #8629
Closes #8640
moraleslazaro/cockpit,stefwalter/cockpit,martinpitt/cockpit,martinpitt/cockpit,cockpit-project/cockpit,martinpitt/cockpit,mvollmer/cockpit,mareklibra/cockpit,andreasn/cockpit,garrett/cockpit,stefwalter/cockpit,moraleslazaro/cockpit,moraleslazaro/cockpit,SotolitoLabs/cockpit,SotolitoLabs/cockpit,deryni/cockpit,garrett/cockpit,andreasn/cockpit,mvollmer/cockpit,cockpit-project/cockpit,mvollmer/cockpit,cockpit-project/cockpit,moraleslazaro/cockpit,SotolitoLabs/cockpit,stefwalter/cockpit,cockpituous/cockpit,martinpitt/cockpit,stefwalter/cockpit,moraleslazaro/cockpit,stefwalter/cockpit,stefwalter/cockpit,martinpitt/cockpit,deryni/cockpit,deryni/cockpit,cockpit-project/cockpit,mareklibra/cockpit,cockpituous/cockpit,stefwalter/cockpit,cockpituous/cockpit,garrett/cockpit,cockpituous/cockpit,mareklibra/cockpit,SotolitoLabs/cockpit,SotolitoLabs/cockpit,moraleslazaro/cockpit,deryni/cockpit,garrett/cockpit,cockpit-project/cockpit,andreasn/cockpit,andreasn/cockpit,cockpituous/cockpit,cockpituous/cockpit,deryni/cockpit,mareklibra/cockpit,mvollmer/cockpit,andreasn/cockpit,SotolitoLabs/cockpit,andreasn/cockpit,deryni/cockpit,moraleslazaro/cockpit,andreasn/cockpit,mareklibra/cockpit,mareklibra/cockpit,SotolitoLabs/cockpit,deryni/cockpit,mareklibra/cockpit,mvollmer/cockpit,garrett/cockpit