Poetry: Python Version constrained packages

Author: tony

poetry.lock

@@ -22,10 +22,19 @@ doc8 = "*"
 docutils = "*"
 flake8 = "*"
 isort = "*"
-pillow = "*"
-pytest = "*"
+pillow = [
+  {version="<7", python="<3"},
+  {version="*", python=">=3"}
+]
+pytest = [
+  {version="<4.7.0", python="<3"},
+  {version="*", python=">=3"}
+]
 pytest-rerunfailures = "*"
-sphinx = "*"
+sphinx = [
+  {version="<2", python="<3"},
+  {version="*", python=">=3"}
+]
 sphinx-issues = "*"
 twine = "*"
 codecov = "*"