Securing many http links to https links

Fix http link to https link for security, modify many link
http to https in the project.

Signed-off-by: Nguyen Hai Truong <truongnh@vn.fujitsu.com>

CONTRIBUTING.md

@@ -13,7 +13,7 @@ If your repo has certain guidelines for contribution, put them here ahead of the
 -->
 
 - [Contributor License Agreement](https://git.k8s.io/community/CLA.md) Kubernetes projects require that you sign a Contributor License Agreement (CLA) before we can accept your pull requests
-- [Kubernetes Contributor Guide](http://git.k8s.io/community/contributors/guide) - Main contributor documentation, or you can just jump directly to the [contributing section](http://git.k8s.io/community/contributors/guide#contributing)
+- [Kubernetes Contributor Guide](https://git.k8s.io/community/contributors/guide) - Main contributor documentation, or you can just jump directly to the [contributing section](https://git.k8s.io/community/contributors/guide#contributing)
 - [Contributor Cheat Sheet](https://git.k8s.io/community/contributors/guide/contributor-cheatsheet) - Common resources for existing developers
 
 ## Mentorship

README.md

@@ -122,7 +122,7 @@ Participation in the Kubernetes community is governed by the [Kubernetes Code of
 [go]: https://golang.org/
 [go-supported]: https://golang.org/doc/devel/release.html#policy
 [docker]: https://www.docker.com/
-[community page]: http://kubernetes.io/community/
+[community page]: https://kubernetes.io/community/
 [Kubernetes Code of Conduct]: code-of-conduct.md
 [Go Report Card Badge]: https://goreportcard.com/badge/sigs.k8s.io/kind
 [Go Report Card]: https://goreportcard.com/report/sigs.k8s.io/kind