ansible-test - add cryptography constraint for cffi (#72761)

The recently released version of cffi fails to install on systems with an older version of gcc. In
our case, this in the CentOS 6 test image. There is a fix but it has not yet been released.

https://foss.heptapod.net/pypy/cffi/-/issues/480

changelogs/fragments/cffi-constraint.yml

@@ -0,0 +1,4 @@
+bugfixes:
+  - >
+    ansible-test - add constraint for ``cffi`` to prevent failure on systems with
+    older versions of ``gcc`` (https://foss.heptapod.net/pypy/cffi/-/issues/480)

test/lib/ansible_test/_data/cryptography-constraints.txt

@@ -1 +1,2 @@
 idna < 2.8 ; python_version < '2.7' # idna 2.8+ requires python 2.7+
+cffi != 1.14.4 # Fails on systems with older gcc. Should be fixed in the next release. https://foss.heptapod.net/pypy/cffi/-/issues/480