build: ensure we're doing prereleases

Author: simon360

package.json

@@ -13,7 +13,7 @@
     "postinstall": "npm-run-all compile",
     "lint": "npm-run-all lint:*",
     "lint:ts": "tslint -c tslint.json './packages/**/*.ts*(x)'",
-    "release": "lerna version",
+    "release": "lerna version prerelease",
     "test": "echo \"Tests coming soon. I'm aware that's not ideal.\""
   },
   "dependencies": {