[es] Update install-kubectl-linux.md

Author: Arhell

content/es/docs/tasks/tools/included/install-kubectl-linux.md

@@ -136,7 +136,7 @@ baseurl=https://packages.cloud.google.com/yum/repos/kubernetes-el7-\$basearch
 enabled=1
 gpgcheck=1
 repo_gpgcheck=1
-gpgkey=https://packages.cloud.google.com/yum/doc/rpm-package-key.gpg
+gpgkey=https://packages.cloud.google.com/yum/doc/yum-key.gpg https://packages.cloud.google.com/yum/doc/rpm-package-key.gpg
 EOF
 yum install -y kubectl
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