Composer Dev(deps-dev): Bump wp-phpunit/wp-phpunit from 6.7.2 to 6.8.0

Bumps [wp-phpunit/wp-phpunit](https://github.com/wp-phpunit/wp-phpunit) from 6.7.2 to 6.8.0.
- [Commits](wp-phpunit/wp-phpunit@6.7.2...6.8.0)

---
updated-dependencies:
- dependency-name: wp-phpunit/wp-phpunit
  dependency-version: 6.8.0
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

composer.json

@@ -51,7 +51,7 @@
 		"wp-forge/helpers": "^2.0"
 	},
 	"require-dev": {
-		"wp-phpunit/wp-phpunit": "^6.7.2",
+		"wp-phpunit/wp-phpunit": "^6.8.0",
 		"yoast/phpunit-polyfills": "^4.0.0",
 		"newfold-labs/wp-php-standards": "^1.2.5",
 		"wp-cli/i18n-command": "^2.6.3"