all: simplify gofmt script

[leighmcculloch]

PR Checklist

PR Structure

• This PR has reasonably narrow scope (if not, break it down into smaller PRs).
• This PR avoids mixing refactoring changes with feature changes (split into two PRs
  otherwise).
• This PR's title starts with name of package that is most changed in the PR, ex.
  services/friendbot, or all or doc if the changes are broad or impact many
  packages.

Thoroughness

• This PR adds tests for the most critical parts of the new functionality or fixes.
• I've updated any docs (developer docs, .md
  files, etc... affected by this change). Take a look in the docs folder for a given service,
  like this one.

Release planning

• I've updated the relevant CHANGELOG (here for Horizon) if
  needed with deprecations, added features, breaking changes, and DB schema changes.
• I've decided if this PR requires a new major/minor version according to
  semver, or if it's mainly a patch change. The PR is targeted at the next
  release branch if it's not a patch change.

Summary

Remove the ls xargs dance from the gofmt and just get gofmt to run it's checks over everything of what's different.

Goal and scope

I was looking at copying this script to another repository and noticed that the dance with excluding certain folders and piping to xargs to run in parallel is really not necessary.

I'm not making this change to improve the performance of this, because I don't think it's meaningful right here, but just mentioning this for completeness that when I run the script as it is now sharing across 4 processes it was actually marginally slower than just running gofmt once like this change does. So this change isn't introducing a slowdown in CI runtime.

Summary of changes

• Remove use of ls, xargs, etc
• Replace with a simple gofmt call

Known limitations & issues

N/A

What shouldn't be reviewed

N/A

[ire-and-curses]

These directories were previously being ignored. Now they're being checked by gofmt. That doesn't sound right?

[leighmcculloch]

Oops, I meant to mention this in the description. vendor no longer exists. Having the docs folder included in the scan is fine, at least today. Looking at the git history of the file and previous PRs didn't tell me why so I can only theorize on why it was included. Maybe an older version of gofmt would error when there were no go files in it. That's what go fmt does today, although not gofmt.

[ire-and-curses]

Gotcha. Yeah it's probably something like that. Pretty sure this was here for a reason in the past, but if it works now, that's great.

[ire-and-curses]

Gotcha. Yeah it's probably something like that. Pretty sure this was here for a reason in the past, but if it works now, that's great.