Reduce noisy NPM output from postinstall script

Basically just replaces this
> sinon@4.4.6 postinstall /home/carlerik/dev/sinon
> node -e "console.log('\u001b[32mLove sinon? You can now support the project via the open collective:\u001b[22m\u001b[39m\n > \u001b[96m\u001b[1mhttps://opencollective.com/sinon/donate\u001b[0m\n')" || exit 0

with this
> sinon@4.4.6 postinstall /home/carlerik/dev/sinon
> node scripts/support-sinon.js

package.json

@@ -33,7 +33,7 @@
     "prepublishOnly": "npm run build",
     "preversion": "./scripts/preversion.sh",
     "postversion": "./scripts/postversion.sh",
-    "postinstall": "node -e \"console.log('\\u001b[32mLove sinon? You can now support the project via the open collective:\\u001b[22m\\u001b[39m\\n > \\u001b[96m\\u001b[1mhttps://opencollective.com/sinon/donate\\u001b[0m\\n')\" || exit 0"
+    "postinstall": "node scripts/support-sinon.js"
   },
   "lint-staged": {
     "*.js": "eslint",

scripts/support-sinon.js

@@ -0,0 +1,6 @@
+"use strict";
+/* eslint-disable no-console */
+console.log(
+    "\u001b[32mLove sinon? You can now support the project via the open collective:" +
+        "\u001b[22m\u001b[39m\n > \u001b[96m\u001b[1mhttps://opencollective.com/sinon/donate\u001b[0m\n"
+);