package/libgsasl: bump to version 1.8.1

- Update hash of README
- Update indentation in hash file (two spaces)

https://lists.gnu.org/archive/html/info-gnu/2020-01/msg00000.html



Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>