ci: drop unneeded setup-python step

Author: henryiii

.github/workflows/sdist.yml

@@ -33,11 +33,6 @@ jobs:
       with:
         fetch-depth: 0
 
-    - name: Set up Python
-      uses: actions/setup-python@v2
-      with:
-        python-version: ${{ matrix.python-version }}
-
     - name: Build pandas sdist
       run: |
         pipx run build --sdist