CI: Update GHA workflow docs

Author: amotl

.github/workflows/docs.yml

@@ -28,7 +28,7 @@ jobs:
         with:
           python-version: '3.12'
           cache: 'pip'
-          cache-dependency-path: 'setup.py'
+          cache-dependency-path: 'pyproject.toml'
 
       - name: Build docs
         run: |