Trying an explicit install of Cython

Author: absurdfarce

.github/workflows/build_wheels_linux.yml

@@ -12,7 +12,9 @@ jobs:
       CIBW_ARCHS_LINUX: x86_64 aarch64
       CIBW_TEST_REQUIRES: pytest mock pure-sasl eventlet
       CIBW_TEST_COMMAND: echo "wheel is installed"
-      CIBW_BEFORE_ALL: yum install -y libev libev-devel
+      CIBW_BEFORE_ALL: >
+        yum install -y libev libev-devel &&
+        pip install cython
       CIBW_ENVIRONMENT: CFLAGS='-s'
     steps:
       - uses: actions/checkout@v4