TST: Use sphinx-automodapi dev with sphinx dev

Author: pllim

tox.ini

@@ -19,7 +19,8 @@ deps =
     sphinx80: sphinx==8.0.*
     sphinx81: sphinx==8.1.*
     sphinx82: sphinx==8.2.*
-    sphinxdev: git+https://github.com/sphinx-doc/sphinx#egg=sphinx
+    sphinxdev: git+https://github.com/sphinx-doc/sphinx
+    sphinxdev: git+https://github.com/astropy/sphinx-automodapi
 
 commands =
     pip freeze