Problem found on alpine linux when trying to `./scripts/feeds update -a`,
which results in `Build dependency: Missing seq command`.
Ref: https://github.com/openwrt/openwrt/pull/1926
Suggested-by: imShara <shara@protonmail.com>
[reworded commit and turned faulty Sob into Suggested-by]
Signed-off-by: Jo-Philipp Wich <jo@mein.io>