[Packer] add vpi repo badge to reflect current openscap score

[barbarello]

As a follow up to Openscap integration with Packer builds story, we would like to provide a badge to the VPI repository such that it would reflect the openscap score obtained from the most recent packer-eks worflow run.
In the future, we may discourage the use of ami builds on the platform when those builds score less than a given gate.