pull namespaces in from d3-selection instead of d3

assets/src/scripts/components/hydrograph/markers.js

-const { namespaces } = require('d3');
-const { select } = require('d3-selection');
+const { select, namespaces } = require('d3-selection');
 
 
 function circleMarker({r, x, y, domId=null, domClass=null}) {