Molecule: Different fix for new Cython

The first attempt (ansible#1492) was unfortunately wrong in two ways. We need
to pin the dependency in inside the container, not as a molecule
dependency. Also it seems like the Cython pin needs to happen *earlier*
but an easy solution is to just pin pyyaml to an old version instead for
now until yaml/pyyaml#601 is resolved.

Signed-off-by: Rick Elrod <rick@elrod.me>

molecule/kind/converge.yml

@@ -15,6 +15,7 @@
           - urllib3==1.26.15
           - docker
           - docker-compose
+          - pyyaml==5.3.1
         state: present
 
     - name: Build operator image

molecule/requirements.txt

@@ -6,4 +6,3 @@ openshift!=0.13.0
 jmespath
 ansible-core
 ansible-compat<4  # https://github.com/ansible-community/molecule/issues/3903
-Cython<3  # https://github.com/yaml/pyyaml/issues/601