[Snyk] Security upgrade postcss-cssnext from 2.11.0 to 3.0.0

[aikar]

Snyk has created this PR to fix one or more vulnerable packages in the `yarn` dependencies of this project.

Changes included in this PR

• Changes to the following files to upgrade the vulnerable dependencies to a fixed version:
  • package.json
  • yarn.lock

Vulnerabilities that will be fixed

With an upgrade:

Severity	Priority Score (*)	Issue	Breaking Change	Exploit Maturity
	551/1000 Why? Recently disclosed, Has a fix available, CVSS 5.3	Regular Expression Denial of Service (ReDoS) SNYK-JS-COLORSTRING-1082939	Yes	No Known Exploit

(*) Note that the real score may have changed since the PR was raised.

Check the changes in this PR to ensure they won't cause issues with your project.

---

Note: You are seeing this because you or someone else with access to this repository has authorized Snyk to open fix PRs.

For more information: 🧐 View latest project report

🛠 Adjust project settings

📚 Read more about Snyk's upgrade and patch logic