Update kubectl and remove nsswitch.conf in flux-cli image

Signed-off-by: Stefan Prodan <stefan.prodan@gmail.com>

Dockerfile

@@ -3,7 +3,7 @@ FROM alpine:3.16 as builder
 RUN apk add --no-cache ca-certificates curl
 
 ARG ARCH=linux/amd64
-ARG KUBECTL_VER=1.25.3
+ARG KUBECTL_VER=1.25.4
 
 RUN curl -sL https://storage.googleapis.com/kubernetes-release/release/v${KUBECTL_VER}/bin/${ARCH}/kubectl \
     -o /usr/local/bin/kubectl && chmod +x /usr/local/bin/kubectl && \
@@ -11,10 +11,6 @@ RUN curl -sL https://storage.googleapis.com/kubernetes-release/release/v${KUBECT
 
 FROM alpine:3.16 as flux-cli
 
-# Create minimal nsswitch.conf file to prioritize the usage of /etc/hosts over DNS queries.
-# https://github.com/gliderlabs/docker-alpine/issues/367#issuecomment-354316460
-RUN [ ! -e /etc/nsswitch.conf ] && echo 'hosts: files dns' > /etc/nsswitch.conf
-
 RUN apk add --no-cache ca-certificates
 
 COPY --from=builder /usr/local/bin/kubectl /usr/local/bin/