change deprecated URL to MonsterDeveloper's book 
change deprecated URL to MonsterDeveloper's book 

The URL https://legacy.gitbook.com/book/monsterdeveloper/writing-telegram-bots-on-java/details seems to be deprecated

https://monsterdeveloper.gitbooks.io/writing-telegram-bots-on-java/content/
rubenlagus/TelegramBots