TOX: Match matplotlib conditions to scipy

Author: effigies

tox.ini

@@ -76,7 +76,8 @@ deps =
   pre: numpy <2.0.dev0
   # Scipy stopped producing win32 wheels at py310
   py3{8,9}-full-x86,x64: scipy >=1.6
-  full,pre: matplotlib >=3.4
+  # Matplotlib depends on scipy, so cannot be built for py310 on x86
+  py3{8,9}-full-x86,x64: matplotlib >=3.4
   # h5py stopped producing win32 wheels at py39
   py38-full-x86,x64: h5py >=2.10
   full,pre: pillow >=8.1