Move testing-library/dom dependency into peerDependencies

[lacolaco]

ATL depends on TL/dom directly, but TL/user-event depends on that via peerDependencies.

https://github.com/testing-library/angular-testing-library/blob/main/projects/testing-library/package.json#L38

https://github.com/testing-library/user-event/blob/main/package.json#L73

In my project, after upgrading ATL to v16, that difference occurred version conflict errors at test. I solved that by adding TL/dom v10 to my own package.json to make TL/user-event to use v10.

I think my situation did not happen if the both libraries depend on TL/dom by the same peerDependencies way.
How do you think? Could we change this dependency? @timdeschryver

[timdeschryver]

Yea, this is similar to testing-library/react-testing-library#1305
Tbh, I liked that users could just install ATL and use it.
But, I think we reached a point where we need to have it as a peerDependency.

I was planning to do that when Angular 18 is released as this would result in a breaking change.

In order to do this we:

• have to move DTL to a peerDependency
• update docs
• install DTL on ng-add
• provide a migration to install DTL

[timdeschryver]

Do you think this should be done earlier? @lacolaco

[lacolaco]

Do you think this should be done earlier? @lacolaco

@timdeschryver No, I don't. It seems reasonable to make this change to coincide with the release for v18.

[timdeschryver]

This will probably land later, as the upgrade to Angular 18 isn't breaking.
If you want to help with this feel free to drop a message and I'll create the beta branch.

[timdeschryver]

For the ones that are interested, there's a WIP available in 17.0.0-beta.3, which has DTL as a peer dependency.