fix: dont conflict with default username var

```bash

# Username

USERNAME=foo-bar

KUBE_USERNAME=foo-bar

# Get the token

TOKEN=$(kubectl create token ${USERNAME} -n kube-system --duration=87600h)

TOKEN=$(kubectl create token ${KUBE_USERNAME} -n kube-system --duration=87600h)

# Get cluster info

CLUSTER_NAME=$(kubectl config view --minify -o jsonpath='{.clusters[0].name}')

CLUSTER_CA=$(kubectl config view --minify --raw -o jsonpath='{.clusters[0].cluster.certificate-authority-data}')

# Create kubeconfig

cat > ${USERNAME}-kubeconfig.yaml <<EOF

cat > ${KUBE_USERNAME}-kubeconfig.yaml <<EOF

apiVersion: v1

kind: Config

clusters:

contexts:

- context:

    cluster: ${CLUSTER_NAME}

    user: ${USERNAME}

  name: ${USERNAME}@${CLUSTER_NAME}

current-context: ${USERNAME}@${CLUSTER_NAME}

    user: ${KUBE_USERNAME}

  name: ${KUBE_USERNAME}@${CLUSTER_NAME}

current-context: ${KUBE_USERNAME}@${CLUSTER_NAME}

users:

- name: ${USERNAME}

- name: ${KUBE_USERNAME}

  user:

    token: ${TOKEN}

EOF