Fix ansible-test coverage constraints.

changelogs/fragments/ansible-test-coverage-constraints.yml

@@ -0,0 +1,2 @@
+bugfixes:
+    - ansible-test - Updated Python constraints for installing ``coverage`` to resolve issues on multiple Python versions when using the ``--coverage`` option.

test/lib/ansible_test/_data/requirements/constraints.txt

@@ -1,5 +1,6 @@
-coverage >= 4.2, < 5.0.0, != 4.3.2 ; python_version <= '3.7' # features in 4.2+ required, avoid known bug in 4.3.2 on python 2.6, coverage 5.0+ incompatible
-coverage >= 4.5.4, < 5.0.0 ; python_version > '3.7' # coverage had a bug in < 4.5.4 that would cause unit tests to hang in Python 3.8, coverage 5.0+ incompatible
+coverage >= 4.5.1, < 5.0.0 ; python_version <  '3.7' # coverage 4.4 required for "disable_warnings" support but 4.5.1 needed for bug fixes, coverage 5.0+ incompatible
+coverage >= 4.5.2, < 5.0.0 ; python_version == '3.7' # coverage 4.5.2 fixes bugs in support for python 3.7, coverage 5.0+ incompatible
+coverage >= 4.5.4, < 5.0.0 ; python_version >  '3.7' # coverage had a bug in < 4.5.4 that would cause unit tests to hang in Python 3.8, coverage 5.0+ incompatible
 cryptography < 2.2 ; python_version < '2.7' # cryptography 2.2 drops support for python 2.6
 deepdiff < 4.0.0 ; python_version < '3' # deepdiff 4.0.0 and later require python 3
 jinja2 < 2.11 ; python_version < '2.7' # jinja2 2.11 and later require python 2.7 or later