Remove unused repo gpgkey for yum repo

microdnf is having issues with the repo gpgkey that was previously used
however the repogpgcheck was removed in
#34546 so the gpgkey for the
repo can be removed as well.

this is to implement #36111

Author: samos123

content/en/docs/setup/production-environment/tools/kubeadm/install-kubeadm.md

@@ -182,7 +182,7 @@ name=Kubernetes
 baseurl=https://packages.cloud.google.com/yum/repos/kubernetes-el7-\$basearch
 enabled=1
 gpgcheck=1
-gpgkey=https://packages.cloud.google.com/yum/doc/yum-key.gpg https://packages.cloud.google.com/yum/doc/rpm-package-key.gpg
+gpgkey=https://packages.cloud.google.com/yum/doc/rpm-package-key.gpg
 exclude=kubelet kubeadm kubectl
 EOF
 

content/en/docs/tasks/tools/install-kubectl-linux.md

@@ -146,7 +146,7 @@ name=Kubernetes
 baseurl=https://packages.cloud.google.com/yum/repos/kubernetes-el7-\$basearch
 enabled=1
 gpgcheck=1
-gpgkey=https://packages.cloud.google.com/yum/doc/yum-key.gpg https://packages.cloud.google.com/yum/doc/rpm-package-key.gpg
+gpgkey=https://packages.cloud.google.com/yum/doc/rpm-package-key.gpg
 EOF
 sudo yum install -y kubectl
 ```