[IN-316]: Update headers constant (#64)

* refactor(lib): assess window type instead of process

* chore(package): v5.0.1

Author: ghermet

package-lock.json

@@ -1,7 +1,7 @@
 {
   "private": false,
   "name": "@what3words/api",
-  "version": "5.0.0",
+  "version": "5.0.1",
   "description": "what3words JavaScript API",
   "homepage": "https://github.com/what3words/w3w-node-wrapper#readme",
   "main": "dist/index.js",

package.json

@@ -6,7 +6,7 @@ export const W3W_REGEX =
 export const VERSION = '__VERSION__';
 export const HEADERS = {
   'X-W3W-Wrapper':
-    typeof process === 'undefined'
+    typeof window !== 'undefined'
       ? `what3words-JavaScript/${VERSION} (${window.navigator.userAgent})`
       : `what3words-Node/${VERSION} (Node ${process.version}; ${getPlatform(
           platform()