Use Alpine image in Dockerfile

For slimmer builds

Author: rmx90210

Dockerfile

@@ -1,5 +1,5 @@
 # adapted from https://nodejs.org/en/docs/guides/nodejs-docker-webapp/
-FROM node:16
+FROM node:16-alpine
 WORKDIR /usr/src/app
 COPY package*.json ./
 RUN npm install