This change adds support for uploading compute packages using memory
instead of loading them from file paths. In order to preserve
backward compatibility, it prioritises the presence of the package path
over the in-memory content. It will only proceed to load from memory
when the package path isn't present.

Signed-off-by: Gorka Lerchundi Osa <glertxundi@gmail.com>

Signed-off-by: Gorka Lerchundi Osa <glertxundi@gmail.com>

It seems like the expected response from Fastly API slightly changed
since it was added the test for invalid packages. Now, instead of
returning package info with zeroed properties, it properly returns a
specific HTTP error (bad request).

This PR changes the test to be compliant with the new behaviour.

Signed-off-by: Gorka Lerchundi Osa <glertxundi@gmail.com>

Signed-off-by: Gorka Lerchundi Osa <glertxundi@gmail.com>

Instead of panic'ing when an error response cannot be decoded from JSON,
return a generic error which includes the read portion of the response
body.

Followup to @dgryski's comment:
#367 (comment)

* feat(resource): implement Resource API

* feat(resource): resource tests

* fix(resources): tests now have fixtures generated

* fix(resources): validation test checks expected error type

* fix(resource): tests weren't correct