nodejs-express: change back into /project dir at the end of build

[Kamran64]

Checklist:

• Read the Code of Conduct and Contributing Guidelines.

• Followed the commit message guidelines.

• Stack adheres to Appsody stack structure.

Modifying an existing stack:

• Updated the stack version in stack.yaml

Because we don't change directory back into /project, there was an error when running the built image as no package.json could be found. This (hopefully) fixes that.

cc @sam-github

Related Issues:

Fixes: #696

[sam-github]

I noticed this while cloning nodejs-express to nodejs-kafka (#698), the changes look good, but I'm puzzled as to why its not caught by the stack tests.

[sam-github]

And also puzzled as to why it doesn't get noticed by appsody run.

[Kamran64]

@sam-github - The stack validation tests currently only check that appsody build passes, without actually verifying that the built app runs. Hence why the travis build was passing previously. This also isn't noticed by appsody run since the changes here only affect the production build (controlled by the /image/project/Dockerfile) and not local development (Dockerfile-stack)

[sam-github]

Manually confirmed this fixes the reported bug:

[Docker] Successfully built 39c9121f999e
[Docker] Successfully tagged dev.local/ex-express:latest
Built docker image dev.local/ex-express
Running command: docker create --name ex-express-extract dev.local/appsody/nodejs-express:0.4
Running command: docker cp ex-express-extract:/config/app-deploy.yaml /home/sam/w/cloud/appsody-stacks/incubator/ex-express/app-deploy.yaml
Running command: docker rm ex-express-extract -f
Created deployment manifest: /home/sam/w/cloud/appsody-stacks/incubator/ex-express/app-deploy.yaml
incubator/ex-express (pr/697 $%) % docker run -it dev.local/ex-express:latest

> nodejs-express@0.4.4 start /project
> node server.js

[Tue Mar  3 23:05:48 2020] com.ibm.diagnostics.healthcenter.loader INFO: Node Application Metrics 5.1.1.202003032304 (Agent Core 4.0.5)
[Tue Mar  3 23:05:49 2020] com.ibm.diagnostics.healthcenter.mqtt INFO: Connecting to broker localhost:1883
App started on PORT 3000
^C% 

[neeraj-laad]

LGTM