fix(*): docker-based build

[vdice]

• Fixes the Docker-based build (transitions to the official golang image in the process)
• Updates CI (brigade.js) to add a test/check for this build
• Adds configurability for interactive Docker runs (necessary for non-interactive CI check)
• Cleans up/refactors a bit of brigade.js in the process to utilize updated utilities (good chance to remove custom code)

Question for reviewers:

I wanted to add a check to ensure functionality of the Docker-based build somewhere in CI, to catch failures like this in the future, but am open to only running it on merges to master (and not on every PR, as is currently implemented). Opinions?

Fixes https://github.com/cnabio/duffle/issues/892

[carolynvs]

What I've done in the past is this:

1. Document in the contributing guide what version of go is required/supported for development. This is just the state of affairs unfortunately.
2. Optionally put in a check in the makefile for the go version if you want to get really strict about it and catch people filing issues about using go 1.14 when you only support go 1.13 for example.
3. Run builds on master that check your supported version(s) of go and tip. Tip should never cause the build/release to fail, but you can use it as an early warning to know that you have work ahead of you, and how bad it looks. I recommend putting that into a separate build, maybe run it on a schedule in addition to commits on master.

[carolynvs]

/brig run

[carolynvs]

@vdice validate examples isn't returning a response back to github. Do you think it's related to this PR?

[vdice]

@vdice validate examples isn't returning a response back to github. Do you think it's related to this PR?

Thank you; yes, something still not right with the runSuite logic in brigade.js... looking/fixing...

[vdice]

@carolynvs fixed now.