chore(deps-dev): bump pestphp/pest from 1.1.0 to 1.6.0

Sourced from pestphp/pest's changelog.

<h2>v1.6.0 (2021-06-18)</h2> <h3>Added</h3>

• Adds a new json expectation method to improve testing with JSON strings (#325)
• Adds dot notation support to the toHaveKey and toHaveKeys expectations (#322)

<h2>v1.5.0 (2021-06-15)</h2> <h3>Changed</h3>

• Moves plugins from the require section to the core itself (#317), (#318), (#320)

<h2>v1.4.0 (2021-06-10)</h2> <h3>Added</h3>

• Support for multiple datasets (Matrix) on the with method (#303)
• Support for incompleted tests (49de462)

<h2>v1.3.2 (2021-06-07)</h2> <h3>Fixed</h3>

• Test cases with the @ symbol in the directory fail (#308)

<h2>v1.3.1 (2021-06-06)</h2> <h3>Added</h3>

• Added for PHPUnit 9.5.5 (#310)

<h3>Changed</h3>

• Lock minimum Pest plugin versions (#306)

<h2>v1.3.0 (2021-05-23)</h2> <h3>Added</h3>

• Named datasets no longer show the arguments (#302)

<h3>Fixed</h3>

• Wraps global functions within function_exists (#300)

<h2>v1.2.1 (2021-05-14)</h2> <h3>Fixed</h3>

• Laravel commands failing with new --test-directory option (#297)

<h2>v1.2.0 (2021-05-13)</h2> <h3>Added</h3>

• Adds JUnit / Infection support (#291)
• --test-directory command line option (#283)

• 9b34650 Adds changelog for 1.6.0
• db9f125 Tags Pest 1.6
• b0e2ce6 Merge pull request #325 from dansysanalyst/feat/json
• 3afdedb Snapshots
• 4bf69b9 feat(json): updates docs
• ecb37fc Refactoring to use toBeJson()
• c1b2757 Method json() to parse JSON strings
• 5116b43 Merge pull request #322 from pestphp/to-have-key
• a5ce2dc Reimplements the new toHaveArray features.
• 729638a release: v1.5.0
• Additional commits viewable in compare view

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