v0.1.0 of thai_promptpay

Pure-Dart PromptPay (Thai EMVCo QR) toolkit: build and parse the QR payload for mobile, National ID / Tax ID and e-Wallet, with amount and CRC validation. Changelog excerpt: - Initial release: encode + decode PromptPay (EMVCo) QR payloads for mobile, National ID / Tax ID and e-Wallet, with amount and CRC validation. Pure Dart.