Update README.md

README.md

 WOLF - Windowed Localization Frames | objectslam Plugin
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-For installation guide and code documentation, please visit the [documentation website](http://mobile_robotics.pages.iri.upc-csic.es/wolf_projects/wolf_lib/wolf_doc/).
+For installation guide and code documentation, please visit the [documentation website](http://mobile_robotics.pages.iri.upc-csic.es/wolf_projects/wolf_lib/wolf-doc-sphinx/).