Fixing wheel builds (#165)

* update cibuildwheel

* windows build

* skip pypy wheel build

* don't build wheels on PR

.github/workflows/wheels.yml

@@ -14,15 +14,11 @@ jobs:
         with:
           submodules: true
           fetch-depth: 0
-      - uses: ilammy/msvc-dev-cmd@v1.7.0
-      - uses: joerick/cibuildwheel@v2.1.2
+      - uses: pypa/cibuildwheel@v2.1.3
         env:
-          CIBW_BUILD: "cp3?-*"
-          CIBW_SKIP: "cp35-* cp36-win* *-win32 *-manylinux_i686"
+          CIBW_SKIP: "pp* *-win32 *-manylinux_i686"
           CIBW_MANYLINUX_X86_64_IMAGE: manylinux2014
           CIBW_ARCHS_MACOS: x86_64 universal2
-          DISTUTILS_USE_SDK: 1
-          MSSdk: 1
       - uses: actions/upload-artifact@v2
         with:
           path: ./wheelhouse/*.whl