Snyk plugin

[dobarx]

Implements:

• data.snyk_issues data source in snyk plugin #68

[traut]

we really should make this a dynamic discovery (for our plugins) with the ability to extend the list with additions from a flat file (or something) 😄 just a note, not in this pull request

[Andrew-Morozko]

LGTM, but the tests would require a bit of a rewrite. After we started using default values and dataspec the plugins can rely on the default values being present and that required values are non-nil. Manually created cty.Values in tests ignore the default values and required value validation checks.

You can take a look at updated tests for the builtin plugins (in #152), I've implemented a function to construct hcl from cty.Value and re-parse it with default values/required values checked appropriately.

In future I guess that tests for "errors if required value is missing" are not needed, the dataspec validates the data already. And after extracting more validation logic into dataspec (like range checks, non empty strings, #158 ) only relatively few niche validation would be made by the plugin code itself.

[dobarx]

Ok, I think I will merge it once I rebase it after your PR #152. Since I see it has some utils for these tests.

[dobarx]

Updated tests using testtools for those spec values. But this did not help much for snyk plugin. Default values for most of the args are nil. Required checks for args org_id & group_id does not work with dataspec because we require one of these two to be set and there is no such constraint ondataspec.