Move copilot version and unit test configurations to pipeline.yml

[adamjkeller]

Problem:

Presently, if one wants to add unit tests (or modify the version of copilot) to a pipeline, they need to modify the buildspec.yml. This can be problematic as the buildspec is loaded with copilot opinionated logic, which one can easily break unknowingly. This is especially difficult for the user experience if they have no understanding of codebuild.

Solution:

Move any user inputs/overrides out of the buildspec into the pipeline.yml file. For the above mentioned use cases:

• Unit tests could live in a "build" stage in the pipeline.yml
• Set copilot version in each stage of the pipeline (example: override to latest copilot version in test, but not production).

[Fodoj]

I would vote for this too. I am indeed changing the buildspec.yml to add tests, because the pipeline is:

• docker-compose up --build
• run tests
• build final image based on previous one, but with removed dev/test dependencies and few extra steps

Would be cool to have a dedicated test stage (though then also could be tricky not to build twice).

[huanjani]

Related #2106

[efekarakus]

Related #2613