Revert "Drop cython dep" (#14884)

* Revert "Remove cython lib"

This reverts commit 46f816e7a4.

* Revert "WIP consider droping cython dep"

This reverts commit 54b32c10f0.

* Update Cython comment

requirements/requirements.in

@@ -9,6 +9,7 @@ botocore
 channels
 channels-redis==3.4.1  # see UPGRADE BLOCKERs
 cryptography>=41.0.2  # CVE-2023-38325
+Cython<3 # this is needed as a build dependency, one day we may have separated build deps
 daphne
 distro
 django==4.2.6  # CVE-2023-43665

requirements/requirements.txt

@@ -88,6 +88,8 @@ cryptography==41.0.3
     #   pyopenssl
     #   service-identity
     #   social-auth-core
+cython==0.29.32
+    # via -r /awx_devel/requirements/requirements.in
 daphne==3.0.2
     # via
     #   -r /awx_devel/requirements/requirements.in