Fix arch issues with kubectl binary

ARG base_image

FROM --platform=${BUILDPLATFORM} alpine:latest AS kubectl

ARG TARGETARCH

WORKDIR /

RUN apk add curl

RUN LATEST=`curl -L -s https://dl.k8s.io/release/stable.txt`; \

    curl -LO "https://dl.k8s.io/release/${LATEST}/bin/linux/${TARGETARCH}/kubectl"

FROM ${base_image:-debian:buster}

LABEL uk.org.kodo.maintainer="Dom Sekotill <dom.sekotill@kodo.org.uk>"

 && ln -sf /dev/stderr /var/log/nginx/error.log \

 &&:

COPY --from=lachlanevenson/k8s-kubectl:latest \

    /usr/local/bin/kubectl /usr/bin/kubectl

COPY --from=kubectl /kubectl /usr/bin/kubectl

ADD monitor.py /usr/bin/monitor

ADD templates /usr/share/nginx/templates