Update README.md - fix broken link to the forum

Author: semhustej

README.md

@@ -27,7 +27,7 @@ should also be mentioned, and the license information if available.
 **Note**: Please DO NOT use accented characters in your file names, thanks!!!
 
 If you are interested in contributing to this library on a more long-term basis, please ask for write 
-access to this repository on this FreeCAD forum thread: http://forum.freecadweb.org/viewtopic.php?f=19&t=4205
+access to this repository on this FreeCAD forum thread: http://forum.freecad.org/viewtopic.php?f=19&t=4205
 
 License
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