再現方法（何をやったら起こったのか詳細に）：
3.5.0.1 から、3.5.1 へバージョンアップしたと後に、
最新話掲載日を確認するとエラーになります。
---
D:\Win_AP\Narou.rb\MyNovel>narou u --gl narou --backtrace
最新話掲載日を確認しています...
C:/Ruby27-x64/lib/ruby/gems/2.7.0/gems/narou-3.5.1/lib/command/update/general_lastup_updater.rb:28:in `block in prepare': undefined method `[]' for nil:NilClass (NoMethodError)
from C:/Ruby27-x64/lib/ruby/2.7.0/forwardable.rb:235:in `each_key'
from C:/Ruby27-x64/lib/ruby/2.7.0/forwardable.rb:235:in `each_key'
from C:/Ruby27-x64/lib/ruby/gems/2.7.0/gems/narou-3.5.1/lib/command/update/general_lastup_updater.rb:25:in `prepare'
from C:/Ruby27-x64/lib/ruby/gems/2.7.0/gems/narou-3.5.1/lib/command/update/general_lastup_updater.rb:17:in `initialize'
from C:/Ruby27-x64/lib/ruby/gems/2.7.0/gems/narou-3.5.1/lib/command/update.rb:238:in `new'
from C:/Ruby27-x64/lib/ruby/gems/2.7.0/gems/narou-3.5.1/lib/command/update.rb:238:in `update_general_lastup'
from C:/Ruby27-x64/lib/ruby/gems/2.7.0/gems/narou-3.5.1/lib/command/update.rb:76:in `block in initialize'
from C:/Ruby27-x64/lib/ruby/2.7.0/optparse.rb:1589:in `block in parse_in_order'
from C:/Ruby27-x64/lib/ruby/2.7.0/optparse.rb:1575:in `catch'
from C:/Ruby27-x64/lib/ruby/2.7.0/optparse.rb:1575:in `parse_in_order'
from C:/Ruby27-x64/lib/ruby/2.7.0/optparse.rb:1569:in `order!'
from C:/Ruby27-x64/lib/ruby/2.7.0/optparse.rb:1666:in `permute!'
from C:/Ruby27-x64/lib/ruby/2.7.0/optparse.rb:1691:in `parse!'
from C:/Ruby27-x64/lib/ruby/gems/2.7.0/gems/narou-3.5.1/lib/commandbase.rb:59:in `execute'
from C:/Ruby27-x64/lib/ruby/gems/2.7.0/gems/narou-3.5.1/lib/command/update.rb:140:in `execute'
from C:/Ruby27-x64/lib/ruby/gems/2.7.0/gems/narou-3.5.1/lib/commandbase.rb:125:in `execute!'
from C:/Ruby27-x64/lib/ruby/gems/2.7.0/gems/narou-3.5.1/lib/commandbase.rb:134:in `execute!'
from C:/Ruby27-x64/lib/ruby/gems/2.7.0/gems/narou-3.5.1/lib/commandline.rb:29:in `run'
from C:/Ruby27-x64/lib/ruby/gems/2.7.0/gems/narou-3.5.1/lib/commandline.rb:43:in `run!'
from C:/Ruby27-x64/lib/ruby/gems/2.7.0/gems/narou-3.5.1/narou.rb:50:in `block in <top (required)>'
from C:/Ruby27-x64/lib/ruby/gems/2.7.0/gems/narou-3.5.1/lib/backtracer.rb:16:in `capture'
from C:/Ruby27-x64/lib/ruby/gems/2.7.0/gems/narou-3.5.1/narou.rb:49:in `<top (required)>'
from C:/Ruby27-x64/lib/ruby/gems/2.7.0/gems/narou-3.5.1/bin/narou:13:in `require_relative'
from C:/Ruby27-x64/lib/ruby/gems/2.7.0/gems/narou-3.5.1/bin/narou:13:in `<top (required)>'
from C:/Ruby27-x64/bin/narou:23:in `load'
from C:/Ruby27-x64/bin/narou:23:in `<main>'
---
