Bump posthtml-expressions from 1.8.0 to 1.8.1

Bumps [posthtml-expressions](https://github.com/posthtml/posthtml-expressions) from 1.8.0 to 1.8.1.
- [Release notes](https://github.com/posthtml/posthtml-expressions/releases)
- [Changelog](https://github.com/posthtml/posthtml-expressions/blob/master/changelog.md)
- [Commits](posthtml/posthtml-expressions@v1.8.0...v1.8.1)

---
updated-dependencies:
- dependency-name: posthtml-expressions
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

package.json

@@ -43,7 +43,7 @@
     "percy": "0.28.6",
     "postcss": "8.3.6",
     "postcss-cli": "8.3.1",
-    "posthtml-expressions": "1.8.0",
+    "posthtml-expressions": "1.8.1",
     "posthtml-include": "1.7.1",
     "posthtml-load-config": "2.0.0",
     "stylelint": "13.13.1",