esm module support

fixes: #655

index.mjs

@@ -0,0 +1,8 @@
+import { createRequire } from 'module';
+const require = createRequire(import.meta.url);
+export const verify = require('./verify.js');
+export const sign = require('./sign.js');
+export const JsonWebTokenError = require('./lib/JsonWebTokenError.js');
+export const NotBeforeError = require('./lib/NotBeforeError.js');
+export const TokenExpiredError = require('./lib/TokenExpiredError.js');
+export const decode = require('./decode');

package.json

@@ -3,6 +3,7 @@
   "version": "9.0.0",
   "description": "JSON Web Token implementation (symmetric and asymmetric)",
   "main": "index.js",
+  "module": "index.mjs",
   "nyc": {
     "check-coverage": true,
     "lines": 95,