Fail execution when high level vulnerabilities found

[ubiratansoares]

We can leverage the output in --json format when summarizing results along with jq to query any existing high level vulnerabilities.

That would reflect in the public API of the Github Action. We can shape the API as

• fail when there are any existing high level vulnerabilities, which translate to a boolean input
• fail when the number of high level vulnerabilities exceeds a thresholds

Example of json output from scan subcommand

 {
  "url":"https://appsweep.guardsquare.com/builds/483c6dc7-ade3-43e3-a0cb-a52976f25440",
  "high":0,
  "medium":2,
  "low":1
}