Update labeler for pylibcudf (rapidsai#16868)

The labeler was not updated for the move of pylibcudf to a separate package.

Authors:
  - Vyas Ramasubramani (https://github.com/vyasr)

Approvers:
  - Bradley Dice (https://github.com/bdice)

URL: rapidsai#16868

.github/labeler.yml

@@ -12,7 +12,7 @@ cudf.polars:
   - 'python/cudf_polars/**'
 
 pylibcudf:
-  - 'python/cudf/pylibcudf/**'
+  - 'python/pylibcudf/**'
 
 libcudf:
   - 'cpp/**'