docs: add kleetus public key to readme
docs: add kleetus public key to readme

bitjson/bitcore,bitjson/bitcore,litecoin-project/litecore,bitjson/bitcore,iobond/bitcore,bitpay/bitcore,bitpay/bitcore,bitpay/bitcore,martindale/bitcore,iobond/bitcore,martindale/bitcore,phplaboratory/bitcore,iobond/bitcore,iobond/bitcore,bitjson/bitcore,martindale/bitcore,iobond/bitcore,bitpay/bitcore,litecoin-project/litecore,martindale/bitcore,phplaboratory/bitcore