Not compatible with Webpack 5 (Next.js 11) (fix)

Hi! 👋

Firstly, thanks for your work on this project! 🙂

Today I used [patch-package](https://github.com/ds300/patch-package) to patch `@amplitude/node@1.10.0` for the project I'm working on.

Here is the diff that solved my problem:

```diff
diff --git a/node_modules/@amplitude/node/esm/src/constants.js b/node_modules/@amplitude/node/esm/src/constants.js
index bae84bb..bc83e29 100644
--- a/node_modules/@amplitude/node/esm/src/constants.js
+++ b/node_modules/@amplitude/node/esm/src/constants.js
@@ -1,5 +1,6 @@
import { LogLevel } from '@amplitude/types';
-export { version as SDK_VERSION } from '../package.json';
+import pkg from '../package.json'
+export var SDK_VERSION = pkg.version;
export var SDK_NAME = 'amplitude-node';
export var AMPLITUDE_SERVER_URL = 'https://api2.amplitude.com/2/httpapi';
export var BASE_RETRY_TIMEOUT_DEPRECATED = 100;
```

This issue body was [partially generated by patch-package](https://github.com/ds300/patch-package/issues/296).