Build Script: Return Code Handling

[StefanS-O]

Hi Dennis,

in the build script, for example here:

https://github.com/denniszielke/phoenix/blob/d33179ac39012fc0eae5981fc096a9d1f613080e/scripts/build_multicalculator.sh#L3

There is no return of the docker build / docker push return code. When the docker build fails, the pipeline still passes, which leads to unexpected results when the deployment to kubernetes happens.

Should i do a pull request, or do you think it would make the example too complicated? Maybe just a comment about the problem in the code, so anybody using something like this in production cough would have less pain :D

This repo has been very helpful, thank you for that!