image: allow creating a zstd-compressed squashfs rootfs · rsalvaterra/openwrt@944e817

Error when evaluating 'strategy' for job 'check-kernel-patches'. openwrt/actions-shared-workflows/.github/workflows/kernel.yml@main (Line: 180, Col: 10): Matrix must define at least one vector

Error when evaluating 'strategy' for job 'build'. openwrt/actions-shared-workflows/.github/workflows/kernel.yml@main (Line: 158, Col: 10): Matrix must define at least one vector