package/jansson: bump to version 2.13.1

- Update hash of LICENSE file (update in year:
  https://github.com/akheron/jansson/commit/2882ead5bb90cf12a01b07b2c2361e24960fae02)
- Update indentation in hash file (two spaces)

https://jansson.readthedocs.io/en/2.13/changes.html#version-2-13-1



Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>