.github/workflows/wheels.yml: use cibuildwheel 1.x to build for Python2

Author: wojdyr

.github/workflows/wheels.yml

@@ -51,7 +51,7 @@ jobs:
     steps:
     - uses: actions/checkout@v2
 
-    - uses: pypa/cibuildwheel@v2.1.1
+    - uses: pypa/cibuildwheel@v1.12.0
       env:
         CIBW_BUILD: ${{ github.event.inputs.cibw_build }}
         CIBW_SKIP: ${{ github.event.inputs.cibw_skip }}