package/pcre: bump version to 8.43

Release notes:
https://lists.exim.org/lurker/message/20190125.161413.ce45dfd2.en.html
https://lists.exim.org/lurker/message/20190223.165009.b0fb3c20.en.html

Updated license hash after update of copyright year in upstream commit
https://vcs.pcre.org/pcre/code/tags/pcre-8.43/LICENCE?r1=1749&r2=1734



Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>