* update nano to 4.2

Release notes at https://nano-editor.org/news.php

2019.04.24 - GNU nano 4.2
* The integrated spell checker does not crash when 'spell' is missing.
* Option --breaklonglines works also when --ignorercfiles is used.
* Automatic hard-wrapping is more persistent in pushing words to the
  same overflow line.

Tested with ipq806x/R7800 and mvebu/WRT3200ACM

Signed-off-by: Hannu Nyman <hannu.nyman@iki.fi>