setup-apkrepos: use wget --spider

the wget -s option was removed in busybox 1.26
https://git.busybox.net/busybox/commit/?id=2972e2c4acb9c46a8cc05c857acac2b3d439bf69

ref #6683

setup-apkrepos.in

@@ -51,7 +51,7 @@ find_fastest_mirror() {
 	for url in $MIRRORS; do
 		# warm up the dns cache
 		nslookup $(get_hostname_from_url $url) >/dev/null 2>&1
-		local time=$(time_cmd wget -q -s -T 5 \
+		local time=$(time_cmd wget --spider -q -T 5 \
 			${url%/}/edge/main/$arch/APKINDEX.tar.gz)
 		if [ -n "$time" ]; then
 			echo "$time $url"