sources: don't escape Unicode characters in tag search URLs.

Fix it so that Unicode characters aren't unnecessarily percent-encoded when generating tag search
URLs. For example, generate URLs like this:

* https://www.pixiv.net/tags/オリジナル/artworks

Not like this:

* https://www.pixiv.net/tags/%E3%82%AA%E3%83%AA%E3%82%B8%E3%83%8A%E3%83%AB/artworks

app/logical/source/extractor/pixiv.rb

@@ -105,7 +105,7 @@ module Source
 
       def tags
         tags = api_illust.dig(:tags, :tags).to_a.map do |item|
-          [item[:tag], "https://www.pixiv.net/tags/#{CGI.escape(item[:tag])}/artworks"]
+          [item[:tag], "https://www.pixiv.net/tags/#{Danbooru::URL.escape(item[:tag])}/artworks"]
         end
 
         if api_illust["aiType"] == 2