Allow to set type for author

Referring to https://schema.org/author the values Organization and Person are supported

lib/jekyll-seo-tag/json_ld_drop.rb

@@ -21,7 +21,9 @@ class JSONLDDrop < Jekyll::Drops::Drop
       private :logo
 
       VALID_ENTITY_TYPES = %w(BlogPosting CreativeWork).freeze
+      VALID_AUTHOR_TYPES = %w(Organization Person).freeze
       private_constant :VALID_ENTITY_TYPES
+      private_constant :VALID_AUTHOR_TYPES
 
       # page_drop should be an instance of Jekyll::SeoTag::Drop
       def initialize(page_drop)
@@ -36,10 +38,13 @@ def fallback_data
       end
 
       def author
+        author_type = page_drop.author["type"]
+
         return unless page_drop.author["name"]
+        return nil if author_type && !VALID_AUTHOR_TYPES.include?(author_type)
 
         {
-          "@type" => "Person",
+          "@type" => author_type || "Person",
           "name"  => page_drop.author["name"],
         }
       end

spec/jekyll_seo_tag/json_ld_drop_spec.rb

@@ -72,6 +72,29 @@
         end
       end
     end
+
+    context "when type Organization" do
+      let(:author) { {"name" => "organization", "type" => "Organization"} }
+
+      it "returns the author with type" do
+        expect(subject).to have_key("author")
+        expect(subject["author"]).to be_a(Hash)
+        expect(subject["author"]).to have_key("@type")
+        expect(subject["author"]["@type"]).to eql("Organization")
+        expect(subject["author"]).to have_key("name")
+        expect(subject["author"]["name"]).to be_a(String)
+        expect(subject["author"]["name"]).to eql("organization")
+      end
+    end
+
+    context "when invalid type" do
+      let(:author) { {"name" => "organization", "type" => "Invalid"} }
+
+      it "returns the author with type" do
+        expect(subject).to have_key("author")
+        expect(subject["author"]).to be nil
+      end
+    end
   end
 
   context "image" do