Test using PHP 8.1 too + fix deprecation warning

• http_build_query(): Passing null to parameter #2 ($numeric_prefix) of type string is deprecated by @macbre in #34
• Test the package using PHP 8.1 too by @macbre in #9

What's Changed

• Bump phpunit/phpunit from 9.5.8 to 9.5.9 by @dependabot in #5
• Bump phpunit/phpunit from 9.5.9 to 9.5.10 by @dependabot in #6
• Bump guzzlehttp/guzzle from 7.3.0 to 7.4.0 by @dependabot in #7
• Bump guzzlehttp/guzzle from 7.4.0 to 7.4.1 by @dependabot in #8
• Bump phpunit/phpunit from 9.5.10 to 9.5.13 by @dependabot in #12
• Bump phpunit/phpunit from 9.5.13 to 9.5.20 by @dependabot in #22
• Bump actions/cache from 2 to 3.0.1 by @dependabot in #21
• Bump guzzlehttp/guzzle from 7.4.1 to 7.4.2 by @dependabot in #20
• Bump actions/checkout from 2 to 3 by @dependabot in #15
• Bump guzzlehttp/guzzle from 7.4.2 to 7.4.3 by @dependabot in #23
• Bump guzzlehttp/guzzle from 7.4.3 to 7.4.4 by @dependabot in #24
• Bump phpunit/phpunit from 9.5.20 to 9.5.21 by @dependabot in #25
• Bump guzzlehttp/guzzle from 7.4.4 to 7.4.5 by @dependabot in #26
• Bump phpunit/phpunit from 9.5.21 to 9.5.25 by @dependabot in #31
• Bump guzzlehttp/guzzle from 7.4.5 to 7.5.0 by @dependabot in #29

New Contributors

• @dependabot made their first contribution in #5

Full Changelog: v1.1.0...v1.2.0