Dropping support for older go versions

[kishaningithub]

I see we are supporting a lot of go versions

stack/.github/workflows/test.yml

Line 14 in e5bbd7d

- 1.7.x

I think we can drop support for versions prior to go modules

#25 (comment)

Keeping the above PR in mind we can keep the minimum to go 1.12

[ChrisHines]

I think that's fair. I have been working on some improvements along those lines in the background, time permitting. The challenge has been that as I worked on expanding the test coverage to handle some of the newer features in Go I discovered that it is tricky to get this package to produce consistent results with various combinations of GOPATH vs. modules and -trimpath or no -trimpath. One of my ideas to work around those challenges involves taking advantage of runtime/debug.BuildInfo (added in Go 1.12), to figure out which parts of the paths are the module path. But testing that has been complicated by golang/go#33976.

[kishaningithub]

In my opinion we can keep the go min version as 1.15