update k8s base url to https://dl.k8s.io

[pixiake]

What type of PR is this?

/kind cleanup

What this PR does / why we need it:

update k8s base url to https://dl.k8s.io https://kubernetes.io/docs/tasks/administer-cluster/kubeadm/change-package-repository/ https://kubernetes.io/docs/tasks/tools/install-kubectl-linux/

Which issue(s) this PR fixes:

Fixes #

Special notes for reviewers:

Does this PR introduced a user-facing change?

update k8s base url to https://dl.k8s.io

Additional documentation, usage docs, etc.:

[kubesphere-prow[bot]]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: pixiake

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files: - ~~[OWNERS](https://github.com/kubesphere/kubekey/blob/master/OWNERS)~~ [pixiake] Approvers can indicate their approval by writing `/approve` in a comment Approvers can cancel approval by writing `/approve cancel` in a comment

[sonarcloud[bot]]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
13.3% Duplication on New Code

See analysis details on SonarCloud

[liangzai006]

/lgtm

[kubesphere-prow[bot]]

LGTM label has been added.

Git tree hash: 91b59d98f71b3564ce5d99919c01b51764bfb69b