fix: Dockerfile to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-ALPINE320-BUSYBOX-7233533
- https://snyk.io/vuln/SNYK-ALPINE320-BUSYBOX-7233533
- https://snyk.io/vuln/SNYK-ALPINE320-BUSYBOX-7233533
- https://snyk.io/vuln/SNYK-ALPINE320-BUSYBOX-7233586
- https://snyk.io/vuln/SNYK-ALPINE320-BUSYBOX-7233586

Dockerfile

@@ -1,6 +1,6 @@
 # syntax = docker/dockerfile:1
 
-FROM alpine:3.20.0
+FROM alpine:3
 RUN apk add --no-cache \
             dhcrelay>=4.4.3 \
             tzdata