In go.mod exclude the old version of testify brought by objx. This
allows to break the dependency cycle and completely remove the
dependency link to old versions of dependencies (some of which had
security issues).
Closes#1292.
go mod edit -exclude=github.com/stretchr/testify@v1.8.2 && go.mod
What
===
Add `go.mod` and `go.sum`, using `Go 1.11`.
Why
===
Now that golang/go#24301 has been accepted, lets start using go.mod files
alongside Godep, and keep the two in sync.
Notes
===
There are no changes required to testify to support go.mod. The files were
generated by running `go build` and `go mod tidy.
Merging
===
This PR is intended to be merged after #659 which adds Go1.11 to the list of
supported builds.