doc: Update the TravisCI package link to use file.io

transfer.sh is no longer available.

Author: thewtex

docs/Build_ITK_Module_Python_packages.rst

@@ -52,11 +52,12 @@ These services use the configurations generated by the `ITKModuleTemplate <https
   Linux Python package wheel links can be found in the CircleCI *Artifacts*
   tab after expanding the available folders.
 
-.. figure:: https://i.imgur.com/Yw3ziU7.png
+.. figure:: https://imgur.com/tHMhTII.png
   :alt: TravisCI Python wheels
 
-  macOS Python package wheels can be downloaded by going to the `transfer.sh`
-  link found in the build output.
+  macOS Python package wheels can be downloaded by visiting to the `file.io`
+  link found in the build output. Note: this link may only be valid for the
+  initial download.
 
 .. figure:: http://imgur.com/Cj5vs3S.png
   :alt: AppVeyor Python wheels