v1.2.0

Added

• TelegramEx.Builder.Sticker for sending stickers (by id, url, file path)
• TelegramEx.Builder.Location for sending geo coordinates
• TelegramEx.Builder.Video for sending videos (by id, url, file path) with duration and cover support
• TelegramEx.Builder.Contact for sending contacts
• Example project in example/ folder as quick review of all features
• Sending messages to concrete threads in forum chats via message_thread_id
• TelegramEx.Router macro to group handlers by logic into routers

Changed

• All builders now accept ctx as the first argument and store payload inside ctx.payload
• API.request/1 accepts full context map instead of separate token, method, payload arguments
• Builders' send/2 delegates to API.request/1 through context — no more Process.get(:token)