Let's do another alpha release to test with 1.21a17

Author: Photonios

setup.py

@@ -36,7 +36,7 @@ def run(self):
 
 setup(
     name="django-postgres-extra",
-    version="1.21",
+    version="1.21a17",
     packages=find_packages(),
     include_package_data=True,
     license="MIT License",