Remove #download and #read

These methods have become obsolete in newer versions of Shrine, as
they can both be implemented in terms of #open.

lib/shrine/storage/fog.rb

@@ -23,18 +23,10 @@ def upload(io, id, **upload_options)
         end
       end
 
-      def download(id)
-        Down.download(url(id))
-      end
-
       def open(id)
         Down.open(url(id))
       end
 
-      def read(id)
-        get(id).body
-      end
-
       def exists?(id)
         !!head(id)
       end

shrine-fog.gemspec

@@ -14,7 +14,7 @@ Gem::Specification.new do |gem|
   gem.files        = Dir["README.md", "LICENSE.txt", "lib/**/*.rb", "*.gemspec"]
   gem.require_path = "lib"
 
-  gem.add_dependency "shrine", "~> 2.0"
+  gem.add_dependency "shrine", "~> 2.2"
   gem.add_dependency "down", ">= 2.3.3"
 
   gem.add_development_dependency "rake"

test/fog_test.rb

@@ -1,6 +1,7 @@
 require "test_helper"
 require "shrine/storage/linter"
 require "uri"
+require "down"
 
 describe Shrine::Storage::Fog do
   def fog(**options)
@@ -35,7 +36,7 @@ def fog(**options)
   describe "#upload" do
     it "assigns the content type" do
       @fog.upload(fakeio, "foo", shrine_metadata: {"mime_type" => "image/jpeg"})
-      tempfile = @fog.download("foo")
+      tempfile = Down.download(@fog.url("foo"))
 
       assert_equal "image/jpeg", tempfile.content_type
     end