update attribution in project.yml

project.yml

@@ -1,7 +1,7 @@
 _prefs: 
   saveCenter: false
 _properties: {}
-attribution: "<a href='http://mapbox.com/about/maps' target='_blank'>Terms & Feedback</a>"
+attribution: "<a href='https://www.mapbox.com/about/maps/' target='_blank'>&copy; Mapbox</a> <a href='https://openstreetmap.org/about/' target='_blank'>&copy; OpenStreetMap</a> <a class='mapbox-improve-map' href='https://www.mapbox.com/map-feedback/' target='_blank'>Improve this map</a>"
 bounds: 
   - -180
   - -85.0511