Make setup.py compatible with newer pip versions.

doc/upgrade.rst

@@ -103,8 +103,6 @@ This version drops Python 2 support.
    existing virtual environment and replace it by the new one so you
    won't have to modify your configuration files.
 
-You will also need to upgrade your pip version to 20.0.2 or newer.
-
 1.14.0
 ======
 

setup.py

@@ -9,7 +9,11 @@ https://packaging.python.org/en/latest/distributing.html
 
 from os import path
 
-from pip._internal.req import parse_requirements
+try:
+    from pip.req import parse_requirements
+except ImportError:
+    # pip >= 10
+    from pip._internal.req import parse_requirements
 
 from setuptools import find_packages, setup
 
@@ -19,7 +23,14 @@ def get_requirements(requirements_file):
     requirements = []
     if path.isfile(requirements_file):
         for req in parse_requirements(requirements_file, session="hack"):
-            requirements.append("%s" % req.requirement)
+            try:
+                if req.requirements.match_markers():
+                    requirements.append("%s;%s" % (req.req, req.markers))
+                else:
+                    requirements.append("%s" % req.req)
+            except AttributeError:
+                # pip >= 20.0.2
+                requirements.append(req.requirement)
     return requirements
 
 
@@ -45,7 +56,7 @@ if __name__ == "__main__":
         classifiers=[
             "Development Status :: 5 - Production/Stable",
             "Environment :: Web Environment",
-            "Framework :: Django :: 1.11",
+            "Framework :: Django :: 2.2",
             "Intended Audience :: System Administrators",
             "License :: OSI Approved :: ISC License (ISCL)",
             "Operating System :: OS Independent",