add grype image to ArtifactHub

[developer-guy]

What would you like to be added:

Why is this needed:

ArtifactHub has a new feature called Container images repositories.

I would like to add Grype container image to ArtifactHub

https://artifacthub.io/docs/topics/repositories/#container-images-repositories

Additional context:

cc: @dirien @Dentrax

[wagoodman]

The artifact in ArtifactHub is currently a test image and needs to be replaced with an official image before this issue can be considered done.

[tgerla]

I believe this is complete--please re-open if I'm wrong!