build(deps-dev): bump postcss from 8.4.25 to 8.4.26

Bumps [postcss](https://github.com/postcss/postcss) from 8.4.25 to 8.4.26.
- [Release notes](https://github.com/postcss/postcss/releases)
- [Changelog](https://github.com/postcss/postcss/blob/main/CHANGELOG.md)
- [Commits](postcss/postcss@8.4.25...8.4.26)

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

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

package.json

@@ -26,7 +26,7 @@
   "devDependencies": {
     "@snowpack/plugin-postcss": "^1.4.3",
     "autoprefixer": "^10.4.14",
-    "postcss": "^8.4.25",
+    "postcss": "^8.4.26",
     "postcss-import": "^15.1.0",
     "snowpack": "^3.8.8",
     "tailwindcss": "^3.3.3"