fix: web/docker/Dockerfile to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-DEBIAN12-IMAGEMAGICK-5660573
- https://snyk.io/vuln/SNYK-DEBIAN12-IMAGEMAGICK-5660573
- https://snyk.io/vuln/SNYK-DEBIAN12-IMAGEMAGICK-5660573
- https://snyk.io/vuln/SNYK-DEBIAN12-IMAGEMAGICK-5660573
- https://snyk.io/vuln/SNYK-DEBIAN12-IMAGEMAGICK-5660573

Author: snyk-bot

web/docker/Dockerfile

@@ -2,7 +2,8 @@
 # rm -rf web/docker/docker_builds/packages/*
 # docker build --tag ruffle-web-docker -f web/docker/Dockerfile .
 # docker cp $(docker create ruffle-web-docker:latest):/ruffle/web/packages web/docker/docker_builds/packages
-FROM node:24
+
+FROM node:24-alpine
 
 # Installing wasm-opt from GitHub:
 # Keep the version number in sync with the ones in the Actions workflows!