docs/helpwanted: fix GL3.txt/features.txt link

Fixes: f926cf5bd0ade3273b32 ("docs: Rename GL3.txt to features.txt")

Signed-off-by: Eric Engestrom <eric@engestrom.ch>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
CC: Andreas Boll <andreas.boll.dev@gmail.com>
1 file changed