feat 🥁: add no-zero-unit rule

This rule enforces unitless zero values in vanilla-extract style objects:
- Automatically removes unnecessary units from zero values
- Handles both positive and negative zero values
- Preserves units where required (time properties, CSS functions)
- Works with all vanilla-extract APIs

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@antebudimir/eslint-plugin-vanilla-extract",
-  "version": "1.7.0",
+  "version": "1.8.0",
   "description": "ESLint plugin for enforcing best practices in vanilla-extract CSS styles, including CSS property ordering and additional linting rules.",
   "author": "Ante Budimir",
   "license": "MIT",