add kubectl

Dockerfile

@@ -2,10 +2,13 @@ FROM ubuntu:20.04
 ARG VAULT_VERSION=1.13.1
 ARG UID=100
 ARG GID=1000
+ARG KUBECTL_VERSION=v1.26.7
 
 RUN groupadd -g "${GID}" vault && mkdir -p /home/vault \
   && usermod -l vault -g "${GID}" -d /home/vault _apt && chown -R vault:vault /home/vault
 
+RUN wget https://dl.k8s.io/release/${KUBECTL_VERSION}/bin/linux/amd64/kubectl -O /usr/local/bin/kubectl && chmod +x /usr/local/bin/kubectl
+
 # Update apt and Install dependencies
 RUN apt-get update && apt install software-properties-common -y && add-apt-repository ppa:rmescandon/yq -y \
     && apt update && DEBIAN_FRONTEND=noninteractive TZ=Etc/UTC apt-get install -y \