fix: Dockerfile to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-UPSTREAM-NODE-3092933
- https://snyk.io/vuln/SNYK-ALPINE315-ZLIB-2976173
- https://snyk.io/vuln/SNYK-UPSTREAM-NODE-3092932
- https://snyk.io/vuln/SNYK-UPSTREAM-NODE-3035795
- https://snyk.io/vuln/SNYK-UPSTREAM-NODE-5741793

Dockerfile

@@ -1,4 +1,4 @@
-FROM node:18.2.0-alpine as builder
+FROM node:18.20.0-alpine as builder
 WORKDIR /build
 COPY . ./
 COPY ./images/ ./static/images