build(deps): Bump css-tree from 2.3.1 to 3.0.1

Bumps [css-tree](https://github.com/csstree/csstree) from 2.3.1 to 3.0.1.
- [Release notes](https://github.com/csstree/csstree/releases)
- [Changelog](https://github.com/csstree/csstree/blob/master/CHANGELOG.md)
- [Commits](csstree/csstree@v2.3.1...v3.0.1)

---
updated-dependencies:
- dependency-name: css-tree
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

package.json

@@ -58,7 +58,7 @@
   },
   "dependencies": {
     "@ember-data/rfc395-data": "^0.0.4",
-    "css-tree": "^2.3.1",
+    "css-tree": "^3.0.1",
     "ember-eslint-parser": "^0.5.4",
     "ember-rfc176-data": "^0.3.18",
     "eslint-utils": "^3.0.0",