Update to latest cibuildwheel.

QuLogic · QuLogic · commit 755cc760737d · 2021-08-19T16:50:19.000-04:00
This is necessary to get the latest PyPy, which implements
`METH_FASTCALL`.
diff --git a/.github/workflows/cibuildwheel.yml b/.github/workflows/cibuildwheel.yml
@@ -47,7 +47,7 @@ jobs:
 
       - name: Install cibuildwheel
         run: |
-          python -m pip install cibuildwheel==1.9.0
+          python -m pip install cibuildwheel==2.1.1
 
       - name: Build minimum NumPy for aarch64
         if: matrix.cibw_archs == 'aarch64' && steps.numpy-cache.outputs.cache-hit != 'true'
