add rougjs to requirements (for sketchmode)

Author: emilykl

package-lock.json

@@ -109,6 +109,7 @@
     "regl-line2d": "^3.1.3",
     "regl-scatter2d": "^3.3.1",
     "regl-splom": "^1.0.14",
+    "roughjs": "^4.6.6",
     "strongly-connected-components": "^1.0.1",
     "superscript-text": "^1.0.0",
     "svg-path-sdf": "^1.1.3",