Add .gitattributes for package distribution

[borkweb]

Excludes development and documentation files from Composer package:

• Development configs (.editorconfig, .gitignore, .gitattributes)
• GitHub workflows
• Documentation folder
• Test files and configs
• Vendor directory

This is, of course, excluding things that are not yet part of the repository but will likely be part of it soon.

[JasonTheAdams]

I'm a touch reluctant to preemptively include things like /docs/, as I'm not aware of that even being discussed yet. But others, like tests, are probably fine.

[borkweb]

I can count on one hand the number of times I've personally looked at documentation in a vendor folder. That number is zero 😁

Ultimately, I can modify it however we want - I was mimicking Guzzle's repo.

[felixarntz]

Thanks @borkweb! Two points of feedback, plus a higher level question: What is the rationale for prefixing some root files with forward slashes while not prefixing others? What's the distinction?

[borkweb]

What is the rationale for prefixing some root files with forward slashes while not prefixing others? What's the distinction?

Any non prefixed item will apply to that file/directory anywhere in the repo. Technically git observes .gitignore and .gitattributes within nested directories and the rules cascade down recursively. For .editorconfig, that gives a project the ability to set different standards in a different directory.

That being said, it is unlikely that those will occur in this repo and we can prefix if we want. I just left them unprefixed because of habit.

[felixarntz]

@borkweb LGTM, just a tiny bit before merge.