libidn2: bump to v2.0.5

libidn2: bump to v2.0.5

* Version 2.0.5 (released 2018-05-18)

** Switched the default library behavior to IDNA2008 as amended
   by TR#46 (non-transitional). That default behavior is enabled when
   no flags are specified to function calls. Applications can utilize the
   %IDN2_NO_TR46 flag to switch to the unamended IDNA2008. This is done in
   the interest of interoperability based on the fact that this is what application
   writers care about rather than strict compliance with a particular protocol.

** Fixed memleak in idn2_to_unicode_8zlz().

** Return error (IDN2_ICONV_FAIL) on charset conversion errors.

** Fixed issue with STD3 rules applying in non-transitional
   TR46 mode.

** idn2: added option --usestd3asciirules.

Signed-off-by: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>