Bump @fullhuman/postcss-purgecss from 4.1.3 to 7.0.2

Bumps [@fullhuman/postcss-purgecss](https://github.com/FullHuman/purgecss) from 4.1.3 to 7.0.2.
- [Release notes](https://github.com/FullHuman/purgecss/releases)
- [Changelog](https://github.com/FullHuman/purgecss/blob/main/CHANGELOG.md)
- [Commits](FullHuman/purgecss@v4.1.3...v7.0.2)

---
updated-dependencies:
- dependency-name: "@fullhuman/postcss-purgecss"
  dependency-type: direct:development
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

package.json

@@ -114,7 +114,7 @@
     "@ember/string": "^3.1.1",
     "@ember/test-helpers": "^3.3.1",
     "@embroider/test-setup": "^3.0.3",
-    "@fullhuman/postcss-purgecss": "^4.1.3",
+    "@fullhuman/postcss-purgecss": "^7.0.2",
     "@release-it-plugins/lerna-changelog": "^7.0.0",
     "broccoli-asset-rev": "^3.0.0",
     "chai": "^4.5.0",