Output boolean values correctly as json
Output boolean values correctly as json

previously 1 was printed instead of true
fixes showing custom keyboards

reo7sp/tgbot-cpp,aadeg/tgbot-cpp,JellyBrick/tgbot-cpp,reo7sp/tgbot-cpp,reo7sp/tgbot-cpp,JellyBrick/tgbot-cpp,JellyBrick/tgbot-cpp,aadeg/tgbot-cpp