package/librsvg: bump to version 2.48.8

package/librsvg: bump to version 2.48.8

- Add a dependency to host-rustc
- libcroco is not a dependency since
  https://gitlab.gnome.org/GNOME/librsvg/-/commit/03ce9bd7875ef2a91979bc4f7d6fa5188cfd785c
- gtk3 is not a dependency since
  https://gitlab.gnome.org/GNOME/librsvg/-/commit/522aeee0ca9b4ff3940bea2d13ebb77ec6c064a6
- cairo script is mandatory since switch to rust

This bump is needed to remove libcroco which has been archived and won't
get any security updates anymore:
https://gitlab.gnome.org/Archive/libcroco/-/issues/8

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>