* Version 2.2.0 (released 2019-05-23)
** Perform A-Label roundtrip for lookup functions by default
** Stricter check of input to punycode decoder
** Fix punycode decoding with no ASCII chars but given delimiter
** Fix 'idn2 --no-tr64' (was a no-op)
** Allow _ as a basic code point in domain labels
** Fail building documentatino if 'ronn' isn't installed
** git tag changed to reflect https://semver.org/