nydusify: add some unit tests for pkg/utils and cmd/nydusify

Signed-off-by: Qinqi Qu <quqinqi@linux.alibaba.com>

wip

Signed-off-by: Peng Tao <bergwolf@hyper.sh>

action: use softprops/action-gh-release to do release

So that we don't rely on the HUB_UPLOAD_TOKEN secret.

Signed-off-by: Peng Tao <bergwolf@hyper.sh>

action: use softprops/action-gh-release to do release

So that we don't rely on the HUB_UPLOAD_TOKEN secret.

Signed-off-by: Peng Tao <bergwolf@hyper.sh>

action: run release test daily

So that if anything breaks, we'd know it early instead of having to find
out upon tagging a new release.

Signed-off-by: Peng Tao <bergwolf@hyper.sh>

action: no more nydus-snapshotter go.sum

Signed-off-by: Peng Tao <bergwolf@hyper.sh>

action: no more nydus-snapshotter go.sum

Signed-off-by: Peng Tao <bergwolf@hyper.sh>

action: publish to crates.io upon release

Signed-off-by: Peng Tao <bergwolf@hyper.sh>

workflow: add workflow to convert top docker hub images

So that we can use them in CI and ref to users to test with.

Signed-off-by: Peng Tao <bergwolf@hyper.sh>

release: include an example nydusd config in the release tarball

So that user can just use it in normal use cases.

Signed-off-by: Peng Tao <bergwolf@hyper.sh>