Update `go.mod`/`go.sum` with indirect dependencies.

[cameronfyfe]

Hi,

First off thanks for writing this tool. I've gotten some good use out of it.

I've just submitted a PR to nixpkgs to add ets to their package repository. One thing I did to achieve a build within the nix sandbox (no internet access during build) was a patch to go.mod and go.sum to make it so all dependencies could be easily pulled into the build sandbox.

I'm not very familiar with standard go workflows so I was unsure if this was something you kept excluded from these files intentionally or not. If they're excluded intentionally or there's a benefit to not adding them feel free to ignore this PR, otherwise it'd be great if these could be updated here, after which I could remove the patch on nixpkgs.