fix: updates Only plugin to check for CI environment

[nhaynes]

What:

• Bug Fix
• New Feature

Description:

Pest v1 had a --ci flag that could be used in CI environments to ignore ->only() calls that were accidentally checked-in to the code base.

This feature looks to have been removed around the release of Pest v2 but it is unlear if it was an intentional choice or simply an omission as a result of a refactor to the ->only() feature. The commit that disabled the feature makes no mention of that intent and remnants of the --ci feature remain in the code base (such as the Environment plugin).

This PR restores the functionality of the --ci flag by updating the Only plugin to check the Environment plugin when it is invoked.

Related:

• Original implementation: Add new --ci option to pest bin #405
• Disabled here: a61db76
• What happened to --ci? #1077

• pest/src/Plugins/Environment.php

  Line 35 in 13f340a

  if ($argument === '--ci') {

[owenvoke]

LGTM. But I'm not sure if this was intentionally removed (I'd probably assume not).