fix dockerfile

Dockerfile

@@ -1,17 +1,21 @@
 ARG SHOUTRRR_VERSION=v0.6.1
 FROM golang:bullseye AS builder
-RUN git clone https://github.com/containrrr/shoutrrr.git shoutrrr && \
+ARG SHOUTRRR_VERSION
-    cd ./shoutrrr && \
+RUN git clone -b ${SHOUTRRR_VERSION} --depth 1 https://github.com/containrrr/shoutrrr.git ./shoutrrr
-    git checkout ${SHOUTRRR_VERSION} && \
+RUN cd ./shoutrrr && \
+    mkdir /output && \
     go build -o /output ./shoutrrr
 
 FROM debian:11-slim
+RUN echo 'debconf debconf/frontend select Noninteractive' | debconf-set-selections
 RUN apt-get update && \
-    apt-get install -y bash curl jq ca-certificates && \
+    apt-get -y --no-install-recommends install \
+      bash \
+      curl \ 
+      jq \
+      ca-certificates && \
     rm -rf /var/lib/apt/lists/*
-
 RUN ln -sf /bin/bash /bin/sh
 WORKDIR /root
-COPY --from=builder /output ./shoutrrr
+COPY --from=builder /output/shoutrrr /usr/bin/shoutrrr
-RUN chmod +x /root/shoutrrr/shoutrrr && \
+RUN chmod +x /usr/bin/shoutrrr
-    ln -sf /root/shoutrrr/shoutrrr /usr/bin/shoutrrr