fix: Dockerfile to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-UPSTREAM-NODE-5811867
- https://snyk.io/vuln/SNYK-ALPINE315-ZLIB-2976173
- https://snyk.io/vuln/SNYK-UPSTREAM-NODE-3326683
- https://snyk.io/vuln/SNYK-UPSTREAM-NODE-5741793
- https://snyk.io/vuln/SNYK-UPSTREAM-NODE-5843454

Dockerfile

@@ -1,4 +1,4 @@
-FROM node:16.14.0-alpine3.15 as builder
+FROM node:20.15-bookworm-slim as builder
 WORKDIR /build
 COPY . ./
 COPY ./images/ ./static/images