redshift: 1.9.1 -> 1.10

Notes:
- The current linking to geoclue2 looks nice but doesn't actually do
  anything. Only clients whitelisted by the geoclue package are
  allowed. Use static locations for now, like the NixOS service does.
- redshift-gtk still needs some work (icon?). It at least runs now,
  but can't control non-user instances like the NixOS service uses.
  This isn't a bug, but will confuse people.
- Add myself as a maintainer.