Fix that only the first attachment per task is downloaded

sort --unique combined with --numeric-sort only check if the first
number is unique ($task_id), which means that only the first attachment
is downloaded. Fixed by switching to uniq for filtering out duplicates.

snapshotter.sh

@@ -105,7 +105,7 @@ function download_attachments() {
     echo "# Task id | Attachment id | Filename" > attachments/attachments.txt
   fi
 
-  { grep --extended-regexp --recursive --only-matching "href=\"https?://bugs.archlinux.org/(task/[0-9]+|)\?getfile=[0-9]+\"" || true; } | sed --regexp-extended 's/task\/([0-9]+).*getfile=([0-9]+)"/\1 \2/' | sort --numeric-sort --unique | while read -r line; do
+  { grep --extended-regexp --recursive --only-matching "href=\"https?://bugs.archlinux.org/(task/[0-9]+|)\?getfile=[0-9]+\"" || true; } | sed --regexp-extended 's/task\/([0-9]+).*getfile=([0-9]+)"/\1 \2/' | sort --numeric-sort | uniq --unique | while read -r line; do
     task_id="${line% *}"
     attachment_id="${line#* }"
     download_attachment "${task_id}" "${attachment_id}"