Merge pull request #2596 from overleaf/jpa-build-scripts-1-3-5

[misc] align the Dockerfile to the build scripts version 1.3.5

GitOrigin-RevId: cdda059b68068b9b4de87520cff91ce179426836

services/web/Dockerfile

@@ -1,7 +1,12 @@
-FROM node:10.19.0 as app
+FROM node:10.19.0 as base
 
 WORKDIR /app
 
+# install_deps changes app files and installs npm packages
+# as such it has to run at a later stage
+
+FROM base as app
+
 #wildcard as some files may not be in all repos
 COPY package.json package-lock.json /app/
 
@@ -10,7 +15,7 @@ RUN npm install --quiet
 
 COPY . /app
 
-FROM node:10.19.0
+FROM base
 
 COPY --from=app /app /app