PHPUnit 9 compatibility #19
Description
When I attempt to composer require this package in my PHPUnit 9 project it fails with the following dependency/version error:
- Root composer.json requires wp-graphql/wp-graphql-testcase ^2.1.3 -> satisfiable by wp-graphql/wp-graphql-testcase[v2.1.3].
- wp-graphql/wp-graphql-testcase v2.1.3 requires phpunit/phpunit ^7.5 || ^8.5.0 -> found phpunit/phpunit[7.5.0, ..., 7.5.20, 8.5.0, ..., 8.5.26] but it conflicts with your root composer.json require (^9.5).
See Supported PHPUnit versions for PHPUnit's release timeline.