migrate to ubuntu base image

Dockerfile

@@ -1,6 +1,6 @@
-FROM docker.io/library/alpine:3.16
+FROM docker.io/library/ubuntu:22.04
 
-# configuration
+# Configuration
 ENV BACKEND_HOST="localhost"
 ENV BACKEND_PORT="3000"
 ENV CACHE_TTL="3600s"
@@ -11,16 +11,16 @@ ENV DISABLE_ERROR_CACHING="true"
 ENV DISABLE_ERROR_CACHING_TTL="30s"
 ENV CONFIG_FILE="default.vcl"
 
-# install some dependencies
-RUN echo "@testing http://dl-cdn.alpinelinux.org/alpine/edge/testing" \
-  >> /etc/apk/repositories
-RUN apk add --no-cache \
+# Install some dependencies
+RUN apt-get update \
+  && apt-get install -y \
   gettext \
   tini \
   varnish \
-  varnish-modules@testing
+  varnish-modules \
+  && apt-get clean
 
-# deploy our custom configuration
+# Deploy our custom configuration
 WORKDIR /etc/varnish
 COPY config/ /templates
 COPY entrypoint.sh /