ci: github api use token for pull requests (#6037)

substrate/.maintain/gitlab/skip_if_draft.sh

@@ -2,7 +2,7 @@
 url="https://api.github.com/repos/paritytech/substrate/pulls/${CI_COMMIT_REF_NAME}"
 echo "[+] API URL: $url"
 
-draft_state=$(curl "$url" | jq -r .draft)
+draft_state=$(curl -H "Authorization: token ${GITHUB_PR_TOKEN}" "$url" | jq -r .draft)
 echo "[+] Draft state: $draft_state"
 
 if [ "$draft_state" = 'true' ]; then