Updated: libjwt 1.15.3

[Daisuke Fujimura via Cygwin-announce]

The following packages have been uploaded to the Cygwin distribution:

* libjwt
* libjwt2
* libjwt-devel

Package summary
* https://cygwin.com/packages/summary/libjwt-src.html

Changelog
* https://github.com/benmcollins/libjwt