ci(docker): separate testing and linting from the build

Creates new CI steps to run the lint and test commands, rather than having them run inside the Docker build. This means
that the image can be built even if there are linting issues (which will be useful for local development), and that the
tests will be able to make use of other processes (and given the app has a reliance on React and Postgres, this is
vital).

Refs #388, #390

.github/workflows/deploy_prereview-dev.yml

@@ -23,6 +23,12 @@ jobs:
     - name: 'Build dev image'
       run: docker-compose --file docker-compose.yml --file docker-compose.dev.yml build prereview
 
+    - name: 'Lint'
+      run: docker-compose --file docker-compose.yml --file docker-compose.dev.yml run --entrypoint "npm run" prereview lint
+
+    - name: 'Test'
+      run: docker-compose --file docker-compose.yml --file docker-compose.dev.yml run --entrypoint "npm run" prereview test
+
     - name: 'Login via Azure CLI'
       uses: azure/login@v1
       with:

Dockerfile

@@ -18,9 +18,6 @@ RUN npm ci
 
 COPY . .
 
-RUN npm run lint
-RUN npm run test
-
 ENV NODE_ENV=production
 
 # Avoid lscpu warning on Alpine