move to alpine

Dockerfile

@@ -1,14 +1,11 @@
-FROM ubuntu:focal
+# hadolint ignore=DL3007
+FROM alpine:latest
 
-# deaktiviert Nachfragen beim installieren von Paketen
-ENV DEBIAN_FRONTEND=noninteractive
-
-# Install necessary packages
-# hadolint ignore=DL3008
-RUN apt-get update && \
-    apt-get -y --no-install-recommends install git openssh-client iputils-ping && \
-		apt-get clean && \
-	  rm -rf /var/lib/apt/lists/* /var/tmp/* /tmp/*
+# hadolint ignore=DL3018
+RUN apk add --no-cache \
+    git \
+    openssh-client \
+    iputils-ping
 
 # Copy the script into the container
 COPY app.sh /app/app.sh