fix(analytics): use more unique chunk name for middleware (#1339)

Fixes issue with Next.js where the "middleware" webpack chunk name
collides with Next.js's middleware.js entrypoint when using the
Node.js runtime.

Based on #1355 by @blurrah.

Author: chenxzhang

.changeset/fix-middleware-chunk-name.md

@@ -0,0 +1,5 @@
+---
+'@segment/analytics-next': patch
+---
+
+Rename middleware chunk name to avoid collision with Next.js middleware entrypoint

packages/browser/src/core/analytics/index.ts

@@ -467,7 +467,7 @@ export class Analytics
   async addSourceMiddleware(fn: MiddlewareFunction): Promise<Analytics> {
     await this.queue.criticalTasks.run(async () => {
       const { sourceMiddlewarePlugin } = await import(
-        /* webpackChunkName: "middleware" */ '../../plugins/middleware'
+        /* webpackChunkName: "analytics-middleware" */ '../../plugins/middleware'
       )
 
       const integrations: Record<string, boolean> = {}