add regl-scatter2d direct to the repo

Author: zhuzhu81998

package-lock.json

@@ -108,7 +108,7 @@
     "probe-image-size": "^7.2.3",
     "regl-error2d": "^2.0.12",
     "regl-line2d": "^3.1.3",
-    "regl-scatter2d": "^3.3.1",
+    "regl-scatter2d": "file:regl-scatter2d",
     "regl-splom": "^1.0.14",
     "strongly-connected-components": "^1.0.1",
     "superscript-text": "^1.0.0",