fix(test-runner-mocha): move @types/mocha to dev dependency

[dgp1130]

Having an @types/* package with global symbols like it and describe forces these global types on downstream consumers which may not use them. TypeScript is fairly aggressive at pulling in globals from transitive dependencies, meaning that @types/mocha is applied to application code, which can cause challenges. For example, Jasmine types overlap and conflict with Mocha types, but transitively including @types/mocha through @web/test-runner-mocha makes Jasmine impossible to use with Web Test Runner. See this commit for a motivating example.

One potential alternative solution I did not explore here but want to state for posterity: I think it is debatable whether @web/test-runner should have a dependency on @web/test-runner-mocha, given that Mocha is only one possible test framework which can be used. If a test environment is using Jasmine or any other framework it would make sense that it should not depend on @web/test-runner-mocha yet that dependency is unavoidable here.

It seemed like Mocha being the default test runner was an intentional decision so I didn't try to change that. However I wonder if the better relationship between these two packages would be an optional peer dependency in @web/test-runner on @web/test-runner-mocha. Set up instructions or a script could configure this peer dependency by default, however I can understand the cost here and why it might be better to always include @web/test-runner-mocha and accept that some users just won't invoke that code path.

I suspect @web/test-runner-mocha also probably wants a peer dependency on mocha to restrict the specific versions which it supports as this seems to be configurable to the user. I think users are supposed to npm install mocha @types/mocha --save-dev as I couldn't find any other non-dev dependency on mocha, though the docs don't state that. I didn't try adding a peer dep in this PR to keep it simple.

What I did

1. Moved @types/mocha to devDependencies.
2. Ran npm install to update the lockfile.
3. This also bumped a few unrelated deps, so I reverted those changes to limit this to just the @types/mocha change.

[changeset-bot]

🦋 Changeset detected

Latest commit: 60dda46

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@web/test-runner-mocha	Patch

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[koddsson]

This looks good I'm not sure about the default test framework discussion but it might be good to talk about. You can open up a discussion about it here in the repo if you'd like.