protobufjs should be a regular dependency (not devDependency)

[jfirebaugh]

protobufjs is in devDependencies:

sketches-js/package.json

Line 44 in 222854e

"protobufjs": "^6.11.3",

But it's required here:

sketches-js/src/ddsketch/proto/compiled.js

Line 4 in 222854e

var $protobuf = require("protobufjs/minimal");

So it should be a regular dependency.