versioned updates, init cleaned up

Dockerfile

@@ -1,6 +1,37 @@
+FROM ghcr.io/linuxserver/baseimage-alpine:3.15 as buildstage
+
+ARG JULIA_VERSION
+
+RUN \
+  apk add --no-cache \
+    curl \
+    jq && \
+  if [ -z "${JULIA_VERSION}" ]; then \
+    JULIA_VERSION=$(curl -sX GET "https://api.github.com/repos/JuliaLang/julia/releases/latest" \
+    | jq -r '. | .tag_name' \
+    | sed 's|^v||'); \
+  fi && \
+  JULIA_MIN_VERSION=$(echo "${JULIA_VERSION}" | cut -d. -f 1,2) && \
+  mkdir -p /root-layer/julia-bins && \
+  echo "**** Downloading x86_64 binary ****" && \
+  curl -f --retry 3 --retry-connrefused \
+    "https://julialang-s3.julialang.org/bin/linux/x64/${JULIA_MIN_VERSION}/julia-${JULIA_VERSION}-linux-x86_64.tar.gz" -o \
+    "/root-layer/julia-bins/julia-x86_64.tar.gz" && \
+  echo "**** Downloading armv7l binary ****" && \
+  curl -f --retry 3 --retry-connrefused \
+    "https://julialang-s3.julialang.org/bin/linux/armv7l/${JULIA_MIN_VERSION}/julia-${JULIA_VERSION}-linux-armv7l.tar.gz" -o \
+    "/root-layer/julia-bins/julia-armv7l.tar.gz" && \
+  echo "**** Downloading aarch64 binary ****" && \
+  curl -f --retry 3 --retry-connrefused \
+    "https://julialang-s3.julialang.org/bin/linux/aarch64/${JULIA_MIN_VERSION}/julia-${JULIA_VERSION}-linux-aarch64.tar.gz" -o \
+    "/root-layer/julia-bins/julia-aarch64.tar.gz"
+
+COPY root/ /root-layer/
+
+# runtime stage
 FROM scratch
 
 LABEL maintainer="MateoPeri"
 
-# copy local files
-COPY root/ /
+# Add files from buildstage
+COPY --from=buildstage /root-layer/ /