Update helm and kubectl versions

Dockerfile

@@ -1,27 +1,36 @@
 FROM ubuntu:latest
 
+ARG TARGETPLATFORM
 ARG TIMEZONE=Etc/UTC
 RUN ln -fs "/usr/share/zoneinfo/$TIMEZONE" /etc/localtime
 
 RUN apt-get update
 RUN apt-get install -y \
     apt-transport-https \
     ca-certificates \
+    curl \
     gnupg2 \
     libpq5 \
     wget \
     unzip
 
-RUN cd `mktemp -d` && \
+RUN mkdir /tmp/install-helm && \
+    cd /tmp/install-helm && \
     wget https://raw.githubusercontent.com/helm/helm/main/scripts/get-helm-3 && \
     chmod +x get-helm-3 && \
-    DEBUG=true USE_SUDO=false DESIRED_VERSION=v3.11.1 ./get-helm-3
+    DEBUG=true USE_SUDO=false DESIRED_VERSION=v3.15.3 ./get-helm-3 && \
+    cd / && \
+    rm -rf /tmp/install-helm
 
-RUN apt-get install -y curl && \
-    curl -fsSLo /usr/share/keyrings/kubernetes-archive-keyring.gpg https://packages.cloud.google.com/apt/doc/apt-key.gpg && \
-    echo "deb [signed-by=/usr/share/keyrings/kubernetes-archive-keyring.gpg] https://apt.kubernetes.io/ kubernetes-xenial main" | tee /etc/apt/sources.list.d/kubernetes.list && \
-    apt-get update && \
-    apt-get install -y kubectl
+RUN mkdir /tmp/install-kubectl && \
+    cd /tmp/install-kubectl && \
+    KUBECTL_VERSION="$(curl -fLs https://dl.k8s.io/release/stable.txt)" && \
+    curl -LOf "https://dl.k8s.io/release/${KUBECTL_VERSION}/bin/${TARGETPLATFORM}/kubectl" && \
+    curl -LOf "https://dl.k8s.io/release/${KUBECTL_VERSION}/bin/${TARGETPLATFORM}/kubectl.sha256" && \
+    echo "$(cat kubectl.sha256) kubectl" | sha256sum --check && \
+    install -o root -g root -m 0755 kubectl /usr/local/bin/kubectl && \
+    cd / && \
+    rm -rf /tmp/install-kubectl
 
 RUN mkdir -p /tmp/awscli2 && \
     cd /tmp/awscli2 && \