Skip packages resource for unsupported OS

[alexpop]

raise "packages resource is not yet supported on #{os.name}" was being hit when inspec check was executed on a non debian OS.

The test will be skipped on unsupported OSes if written like this:

  describe packages(/bash/) do
    its("names") { should be_empty }
  end

But succeed when written like this, hence the warn in filtered_packages:

  describe packages(/bash/).names do
    it { should be_empty }
  end

More about this limitation here: #1205 (comment)

[arlimus]

Awesome bugfix Alex, just one more tiny addition ;)

[arlimus]

Could we please add skip_resource for all those operating systems where this is not supported?

[alexpop]

I've done it in initialize:
return skip_resource "The packages resource is not yet supported on OS #{inspec.os.name}" unless @command

[arlimus]

Ah perfect, I missed that! Thank you 👍

[arlimus]

Kudos Alex!!

[alexpop]

Code shipped in inspec 1.14.1