chore: avoid apparent race condition in Make task execution

[ctreatma]

This is a weird one...somehow, switching to running Go commands in a container (#14), combined with the passage of time (worked fine for me last week, consistently doesn't this week) has broken the make generate-all task (and the underlying make -f Makefile.metalv1 generate task). But only when I'm running locally.

In CI, make generate-all runs just fine (as it used to do for me locally). Today, locally, it fails every time. After digging through loads of console output I found this message about halfway through:

docker  run --rm -u 502:20 -v /Users/ctreatman/Documents/code/equinix-sdk-go:/workdir -w /workdir -e GOCACHE=/tmp/.cache golang:1.19 go mod tidy
go: warning: "all" matched no packages

As a result of this failed execution, the go.mod and go.sum don't declare any dependencies, which eventually causes the Go tests to fail.

[ctreatma]

As a first pass I've made mod a prerequisite for test and removed it from the prerequisites list for generate in the SDK Makefile(s). This works for now but I think the actual race involves mod running before remove-unused has finished removing the generated <service>/go.(mod|sum) files. A more direct fix might be to have the mod task remove generated service-specific go.mod and go.sum files instead.

[cprivitere]

Just checked this out and tried building on my linux server, seems to run fine at least.

[ctreatma]

I ended up updating the mod task to clean up the extra go.mod and go.sum files and reordering the prerequisites for generate and that approach seems to work to. Let me know if you prefer the earlier version of this PR instead, though.

[cprivitere]

No, I prefer this way.

[cprivitere]

lgtm

[github-actions]

This PR is included in version 0.31.2 🎉