Fix the dev image

Author: toolmantim

Diff for: Dockerfile

@@ -1,6 +1,11 @@
-FROM node:12-alpine@sha256:0b5c7eb38785da1ad4c105930faca0bc546dfcceb0464724456e277fd5e3f6e2
+FROM node:12-alpine@sha256:0b5c7eb38785da1ad4c105930faca0bc546dfcceb0464724456e277fd5e3f6e2 as base
 WORKDIR    /src
 ENV        PATH=$PATH:/src/bin PLUGIN_PATH=/plugin
 ADD        . /src/
 RUN        npm ci
-ENTRYPOINT ["lint"]
+ENTRYPOINT ["lint"]
+
+FROM base as dev
+RUN npm -s install
+
+FROM base

Diff for: Dockerfile.dev

@@ -1,4 +1,4 @@
-version: '3.2'
+version: '3.4'
 services:
   linter:
     build: .

Diff for: docker-compose.prod.yml

@@ -1,9 +1,9 @@
-version: '3.2'
+version: '3.4'
 services:
   linter:
     build:
       context: .
-      dockerfile: Dockerfile.dev
+      target: dev
     volumes:
       # Mount these in so we pick up edits in dev, without having to re-build
       - "./bin:/src/bin"