TOX: Enable pydicom@master for dev test

Author: effigies

tox.ini

@@ -99,9 +99,8 @@ deps =
   full,pre,dev: pillow >=8.1
   full,pre,dev: indexed_gzip >=1.4
   full,pre,dev: pyzstd >=0.14.3
-  full,pre,dev: pydicom >=2.1
-  # pydicom master seems to be breaking things
-  # pre: pydicom @ git+https://github.com/pydicom/pydicom.git@main
+  full,pre: pydicom >=2.1
+  dev: pydicom @ git+https://github.com/pydicom/pydicom.git@main
 
 commands =
   pytest --doctest-modules --doctest-plus \