[CI] Build/Test Improvement suggestions from EIO

[mallardduck]

• - It looks like you could probably do a go mod download prior to tests/builds, if you wanted to cache that.
• - 76sec to build the binary, might be throwing a few more CPU cores at it to see how much it cuts down?
• - Not performance related, but you may want to consider adding -s to your GOLDFLAGS (which doesn’t break stack traces, unlike post-processing it with strip can do), and possible -w (unless the app uses or exposes an interface for pprof profiling info). Both of those can cut down your binary size, and smaller containers are better for everyone.

NOTE: just for long term tracking and memory here. Not a call to action.