Release readxl 1.4.2 about readxl

[jennybc]

ERRORs and more from rchk, but all uninformative. The ERRORs:

ERROR: too many states (abstraction error?) in function strptime_internal
ERROR: too many states (abstraction error?) in function RunGenCollect

Then lots and lots of "has address taken, results will be incomplete":

Function SheetView<Xls>::readCols(cpp11::r_vector<cpp11::r_string>, std::__1::vector<ColType, std::__1::allocator<ColType> > const&, StringSet const&, bool, bool)
  [UP] ignoring variable <unnamed var:   %26 = alloca %struct.SEXPREC*, align 8> as it has address taken, results will be incomplete 

[jennybc]

rhub::check_with_sanitizers() was uninformative as everything seemed to be about cpp11, not readxl, and seemed to be complaining about the use of C++11.