parse runc-version, not go.mod (vendor.conf)

[AkihiroSuda]

containerd-nightlies/.github/workflows/main.yml

Lines 38 to 44 in fe50612

	if [ -f go.mod ]; then
	RUNC_COMMIT=$(grep opencontainers/runc go.mod | awk '{print $2}')
	else
	# containerd 1.4 and lower use vendor.conf for the modules
	RUNC_COMMIT=$(grep opencontainers/runc vendor.conf | awk '{print $2}')
	fi
	echo "RUNC_COMMIT=${RUNC_COMMIT}" >> $GITHUB_ENV

This version detection logic is not robust.
As the result, https://github.com/kind-ci/containerd-nightlies/releases/tag/containerd-1.5.1 was released with an unexpected version of runc (expected: rc94, actual: rc93).

The right way is to read script/setup/runc-version.

https://github.com/containerd/containerd/blob/v1.4.5/script/setup/runc-version
https://github.com/containerd/containerd/blob/v1.5.1/script/setup/runc-version

[AkihiroSuda]

PR #20

[BenTheElder]

thanks, the previous solution was rushed to unblock some kubernetes CI testing and is definitely not robust enough.

[BenTheElder]

I am re-running the nightlies after deleting v1.5.1 in particular.