version: bump to 0.1.5 (#216)

* Bump version to 0.1.5

* Update changelog

packages/contracts/CHANGELOG.md

 # Changelog
 
+## v0.1.5
+
+Various cleanup and maintenance tasks.
+
+- Improving comments and some names (#211)
+- Add descriptive comments above the contract declaration for all 'non-abstract contracts' (#200)
+- Add generic mock xdomain messenger (#209)
+- Move everything over to hardhat (#208)
+- Add comment to document v argument (#199)
+- Add security related comments (#191)
+
 ## v0.1.4
 
 Fix single contract redeployment & state dump script for

packages/contracts/package.json

 {
   "name": "@eth-optimism/contracts",
-  "version": "0.1.4",
+  "version": "0.1.5",
   "main": "build/src/index.js",
   "files": [
     "build/**/*.js",