test: allow executing a single test

Move the `test` call at the top level so that we
can use `test.only`.

Author: ludofischer

package.json

@@ -47,7 +47,7 @@
     "postcss": "^8.2.2",
     "rimraf": "^3.0.2",
     "typescript": "^4.5.4",
-    "uvu": "^0.5.2"
+    "uvu": "^0.5.3"
   },
   "dependencies": {
     "postcss-selector-parser": "^6.0.2",