update dependency spec

Author: bckohan

pyproject.toml

@@ -45,10 +45,11 @@ exclude = ["render_static/tests"]
 # django-renderstatic = 'render_static.console:main'
 
 [tool.poetry.dependencies]
-python = "^3.6"
+python = ">=3.6,<4.0"
 Django = [
-    {version = "^2.2||^3.0", python = "^3.6"},
-    {version = "^4.0", python = "^3.8"}
+    {version = ">=2.2,<3.0", python = ">=3.6,<=3.9"},
+    {version = ">=3.0,<4.0", python = ">=3.6,<=3.10"},
+    {version = ">=4.0,<5.0", python = ">=3.8,<4.0"}
 ]
 
 Jinja2 = { version = ">=2.9,<4.0", optional = true }