chore(release): 4.0.0 [skip ci]

# [4.0.0](v3.0.0...v4.0.0) (2020-10-26)

### Bug Fixes

* future proof against metamask breaking changes ([47e9727](47e9727))

### BREAKING CHANGES

* Metamask legacy versions that use `window.web3` are no longer supported

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@polymathnetwork/sdk",
-  "version": "3.0.0",
+  "version": "4.0.0",
   "description": "A Javascript SDK for interacting with the Polymath network for the browser and Node.js",
   "bugs": {
     "url": "https://github.com/PolymathNetwork/polymath-sdk/issues"