[feature] Added a CLI flag to allow passing without any test files found

[glektarssza]

What I did

1. Added a CLI flag that allows passing without any test files being found.
2. Added documentation for the above new CLI flag.
3. Added a Git ignore line for local environment files (e.g. .envrc).

Would resolve #1331

[changeset-bot[bot]]

🦋 Changeset detected

Latest commit: dcaff84406f75250136fe7e21956c2a405e79c02

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

This PR includes changesets to release 12 packages

Name	Type
@web/test-runner-core	Minor
@web/test-runner	Minor
@web/test-runner-chrome	Patch
@web/test-runner-commands	Patch
@web/test-runner-coverage-v8	Patch
@web/test-runner-junit-reporter	Patch
@web/test-runner-mocha	Patch
@web/test-runner-playwright	Patch
@web/test-runner-puppeteer	Patch
@web/test-runner-selenium	Patch
@web/test-runner-visual-regression	Patch
@web/test-runner-webdriver	Patch

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[Westbrook]

Could you add a change set as requested above?

[glektarssza]

I will add one after work today.

[glektarssza]

Changeset added, @Westbrook. I think the bot's comment is completely out to lunch now, though, because of the merge commit in a957ff9.

[Westbrook]

Thanks for getting the changeset it. That is looking fine. Can you check in the CI output? Once that’s green we should be good to edge this.

[glektarssza]

Will take a look tonight!