message: Don't prefix QR codes with the length of the static marker string
  Fixes
diff: @@ -130,9 +130,9 @@ export default class VerificationQRCode extends React.PureComponent {
  tmpBuf.writeInt8(i, 0);
  buf = Buffer.concat([buf, tmpBuf]);
  };
  - const appendStr = (s: string, enc: string) => {
  + const appendStr = (s: string, enc: string, withLengthPrefix = true) => {
  const tmpBuf = Buffer.from(s, enc);
  - appendInt(tmpBuf.byteLength);
  + if (withLengthPrefix) appendInt(tmpBuf.byteLength);
  buf = Buffer.concat([buf, tmpBuf]);
  };
  const appendEncBase64 = (b64: string) => {
  @@ -142,7 +142,7 @@ export default class VerificationQRCode extends React.PureComponent {
  };
  // Actually build the buffer for the QR code
  - appendStr(this.props.prefix, "ascii");
  + appendStr(this.props.prefix, "ascii", false);
  appendByte(this.props.version);
  appendByte(this.props.mode);
  appendStr(this.props.transactionId, "utf-8");
  