package/libsigsegv: bump version to 2.13

Removed patches applied upstream:

0001-Improve-support-for-Linux-RISC-V.patch
https://github.com/roswell/libsigsegv/commit/671b2528b55c57eda1a8fe5872ff1ef61014235f

0002-m4-stack-direction-RISC-V-stack-grows-downward.patch
https://github.com/roswell/libsigsegv/commit/fd0e3d99d109b46d73ef37f38a23076f5acd1053

0003-Improve-support-for-Linux-nds32.patch
0004-m4-stack-direction-NDS32-stack-grows-downward.patch
https://github.com/roswell/libsigsegv/commit/51a03192a3e024931309bdf11a9c055985de0ddf

Reformatted hashes.

Release notes: https://github.com/roswell/libsigsegv/blob/master/NEWS



Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>