feat: support loading config with tsx (#260)

Author: privatenumber

README.md

@@ -100,6 +100,9 @@ In this case create JS/TS file named:
 - `postcss.config.mts`
 - `postcss.config.cts`
 
+> [!NOTE]  
+> For TypeScript configs, you must have [tsx](https://www.npmjs.com/package/tsx) or [jiti](https://www.npmjs.com/package/jiti) installed as a peer dependency.
+
 ```
 Project (Root)
   |– client

package.json

@@ -53,18 +53,23 @@
     "postcss-import": "^16.1.0",
     "postcss-nested": "^6.0.1",
     "sugarss": "^4.0.1",
+    "tsx": "^4.8.2",
     "typescript": "5.4.5"
   },
   "peerDependencies": {
     "jiti": ">=1.21.0",
-    "postcss": ">=8.0.9"
+    "postcss": ">=8.0.9",
+    "tsx": "^4.8.1"
   },
   "peerDependenciesMeta": {
     "jiti": {
       "optional": true
     },
     "postcss": {
       "optional": true
+    },
+    "tsx": {
+      "optional": true
     }
   },
   "c8": {