bump alpine to 3.20

Signed-off-by: Adam Warner <me@adamwarner.co.uk>

src/Dockerfile

@@ -1,6 +1,6 @@
 # syntax=docker/dockerfile:1
 ARG FTL_SOURCE=remote
-ARG alpine_version="3.19" 
+ARG alpine_version="3.20" 
 FROM alpine:${alpine_version} AS base
 # https://docs.docker.com/engine/reference/builder/#automatic-platform-args-in-the-global-scope
 

test/Dockerfile

@@ -1,5 +1,5 @@
-ARG alpine_version="3.19"
-ARG docker_version="25.0.4"
+ARG alpine_version="3.20"
+ARG docker_version="27.1.1"
 
 FROM docker:${docker_version}-cli-alpine${alpine_version}