package/libwpe: bump to version 1.2.1

This is a bugfix release of libwpe, which fixes an issue with memory
allocation for the pasteboard, adds some missing Unicode-to-KeySym
conversions, and fixes a build issue. Full release notes:

  https://wpewebkit.org/release/libwpe-1.2.1.html



Signed-off-by: Adrian Perez de Castro <aperez@igalia.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>