python_requirements_info - fail when version operator used without version (#3785)

* python_requirements_info - fail when version operator used without version

* added changelog fragment

* simplified way of achieving the same result

tests/integration/targets/python_requirements_info/tasks/main.yml

@@ -25,3 +25,15 @@
     that:
       - "'installed' in dep_info.valid.pip"
       - "'notreal' in dep_info.not_found"
+
+- name: wrong specs
+  python_requirements_info:
+    dependencies:
+      - ansible<
+  register: wrong_spec1
+  ignore_errors: true
+
+- name: ensure wrong specs return error
+  assert:
+    that:
+      - wrong_spec1 is failed