[Bug] Cannot upload files with size > 2GB

[schechi1190]

FakeS3 standalone server errors out for upload of files > 2GB. Seems like the file data is being concatenated into a string whic has max length of 2GB:

127.0.0.1 - - [08/Apr/2020:14:40:50 Pacific Daylight Time] "POST /hpcpr-na/L48748-DN1_Win10RS5-amd64-PR-Americas.wim?uploadId=a2856cb794f58306117523890de3d024 HTTP/1.1" 500 315

• -> /hpcpr-na/L48748-DN1_Win10RS5-amd64-PR-Americas.wim?uploadId=a2856cb794f58306117523890de3d024
  [2020-04-08 14:42:47] ERROR ArgumentError: string sizes too big
  C:/Ruby27-x64/lib/ruby/gems/2.7.0/gems/fakes3-2.0.0/lib/fakes3/file_store.rb:248:in block in combine_object_parts' C:/Ruby27-x64/lib/ruby/gems/2.7.0/gems/fakes3-2.0.0/lib/fakes3/file_store.rb:240:in each'
  C:/Ruby27-x64/lib/ruby/gems/2.7.0/gems/fakes3-2.0.0/lib/fakes3/file_store.rb:240:in combine_object_parts' C:/Ruby27-x64/lib/ruby/gems/2.7.0/gems/fakes3-2.0.0/lib/fakes3/server.rb:280:in do_POST'
  C:/Ruby27-x64/lib/ruby/2.7.0/webrick/httpservlet/abstract.rb:105:in service' C:/Ruby27-x64/lib/ruby/2.7.0/webrick/httpserver.rb:140:in service'
  C:/Ruby27-x64/lib/ruby/2.7.0/webrick/httpserver.rb:96:in run' C:/Ruby27-x64/lib/ruby/2.7.0/webrick/server.rb:307:in block in start_thread'