Release v4.0.0

Breaking changes:

- Requires Node-API v8 e.g. Node.js >= 16
- Returns 64-bit values as BigInt
- Sets FARMHASH_DEBUG=0 at compile time

package.json

@@ -1,6 +1,6 @@
 {
   "name": "farmhash",
-  "version": "3.3.1",
+  "version": "4.0.0",
   "author": "Lovell Fuller <[email protected]>",
   "contributors": [
     "Matt Ranney  <[email protected]>",