Log Message:
tex-hyperref{,-doc}: update to 6.88e

Update to hyperref fixing issues as reported on GitHub
recent ChangeLog entries:

2018-11-30 6.88e Ulrike Fischer
 * added ignorespaces to footnotetext to address

2018-11-27 6.88d Ulrike Fischer
 * removed wrong producer warning for xetex and (x)dvipdfm(x)

2018-11-22 6.88c Ulrike Fischer
 * Added support for pdflinkmargin for xetex

2018-11-17 6.88b David Carlisle
 * Ensure Producer field in PDF shows LuaTeX version with two digits