Update Django requirement to >=6.0a1,<6.1

Amp-Thread-ID: https://ampcode.com/threads/T-1ae0efd4-afab-468c-b53b-30d0573c635e
Co-authored-by: Amp <[email protected]>

Author: vinitkumar

tests/requirements/dj60_cms50.txt

@@ -2,7 +2,7 @@
 
 django-cms>=5.0,<5.1
 
-Django>=6.0,<6.1
+Django>=6.0a1,<6.1
 django-classy-tags
 django-fsm>=2.6,<3
 django-sekizai