Update Dockerfile

Dockerfile

@@ -2,15 +2,17 @@
 FROM node:14-bullseye-slim as build-step
 WORKDIR /app
 ENV PATH /app/node_modules/.bin:$PATH
-
-# Copy package.json and package-lock.json first to leverage Docker cache
+RUN mkdir ./frontend
 COPY ./frontend/package.json ./frontend/package-lock.json ./frontend/
 WORKDIR /app/frontend
 RUN npm install -g [email protected]
+# It's OK to have multiple consecutive `RUN` instructions.
+# hadolint ignore=DL3059
 RUN npm install
 
-# Copy the rest of the frontend code and build the project
+WORKDIR /app
 COPY ./frontend ./frontend
+
 WORKDIR /app/frontend
 RUN npm run build