Skip building musllinux

It appears newer cibuildwheel versions try to build for more platforms.
epicscorelibs doesn't support musllinux, so skip building there.

Author: AlexanderWells-diamond

.github/workflows/code.yml

@@ -77,6 +77,7 @@ jobs:
           CIBW_REPAIR_WHEEL_COMMAND: ""
           CIBW_MANYLINUX_X86_64_IMAGE: manylinux1
           CIBW_ENVIRONMENT_LINUX: SETUPTOOLS_DSO_PLAT_NAME=manylinux1_x86_64
+          CIBW_SKIP: ${{ matrix.python }}*64-musllinux*
 
       - name: Upload Wheel and Sdist
         uses: actions/upload-artifact@v2