Bump the dev-dependencies group with 2 updates

Bumps the dev-dependencies group with 2 updates: [@tailwindcss/postcss](https://github.com/tailwindlabs/tailwindcss/tree/HEAD/packages/@tailwindcss-postcss) and [tailwindcss](https://github.com/tailwindlabs/tailwindcss/tree/HEAD/packages/tailwindcss).


Updates `@tailwindcss/postcss` from 4.1.7 to 4.1.8
- [Release notes](https://github.com/tailwindlabs/tailwindcss/releases)
- [Changelog](https://github.com/tailwindlabs/tailwindcss/blob/main/CHANGELOG.md)
- [Commits](https://github.com/tailwindlabs/tailwindcss/commits/v4.1.8/packages/@tailwindcss-postcss)

Updates `tailwindcss` from 4.1.7 to 4.1.8
- [Release notes](https://github.com/tailwindlabs/tailwindcss/releases)
- [Changelog](https://github.com/tailwindlabs/tailwindcss/blob/main/CHANGELOG.md)
- [Commits](https://github.com/tailwindlabs/tailwindcss/commits/v4.1.8/packages/tailwindcss)

---
updated-dependencies:
- dependency-name: "@tailwindcss/postcss"
  dependency-version: 4.1.8
  dependency-type: direct:development
  update-type: version-update:semver-patch
  dependency-group: dev-dependencies
- dependency-name: tailwindcss
  dependency-version: 4.1.8
  dependency-type: direct:development
  update-type: version-update:semver-patch
  dependency-group: dev-dependencies
...

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

Author: dependabot[bot]

package-lock.json

@@ -38,7 +38,7 @@
     "@metalsmith/layouts": "^3.0.0",
     "@metalsmith/markdown": "^1.10.0",
     "@metalsmith/permalinks": "^3.2.0",
-    "@tailwindcss/postcss": "^4.1.7",
+    "@tailwindcss/postcss": "^4.1.8",
     "autoprefixer": "^10.4.21",
     "browser-sync": "^3.0.4",
     "chokidar-cli": "^3.0.0",