Trivia: fixed rozdilne verze knihoven v requirements dev a base

requirements/dev.txt

@@ -4,7 +4,7 @@
 #
 #    pip-compile dev.in
 #
-attrs==20.3.0             # via pytest
+attrs==20.2.0             # via pytest
 coverage==5.3             # via pytest-cov
 factory-boy==3.1.0        # via pytest-factoryboy
 faker==4.17.1             # via factory-boy