Update projects.yaml

Author: ninamiolane

projects.yaml

@@ -215,7 +215,7 @@ projects:
     github_id: geomstats/geomstats
     pypi_id: geomstats
     conda_id: conda-forge/geomstats
-    docs_url: https://geomstats.ai
+    docs_url: https://geomstats.github.io/
     category: ml-frameworks
   - name: Theano
     github_id: Theano/Theano