在创建了.env文件后，运行flutter pub run build_runner build --delete-conflicting-outputs报错

[AChaoZJU]

An exmaple .env

## 根据你的需要配置
OPENAI_API_KEY=sk-aaaaaaaaaaaa
HTTP_PROXY=http://localhost:7890
BASE_URL=https://openai.mignsin.workers.dev/v1

➜ chatgpt_book_code git:(chapter-4) ✗ flutter pub run build_runner build --delete-conflicting-outputs

Deprecated. Use `dart run` instead.
[INFO] Generating build script...
[INFO] Generating build script completed, took 380ms
[INFO] Reading cached asset graph completed, took 122ms
[INFO] Checking for updates since last build completed, took 943ms
[INFO] Running build completed, took 20ms
[INFO] Caching finalized dependency graph completed, took 97ms
[SEVERE] envied_generator:envied on lib/env.dart (cached):

Environment variable not found for field `apiKey`.
package:chatgpt/env.dart:8:16
  ╷
8 │   static const apiKey = _Env.apiKey;
  │                ^^^^^^
  ╵
[SEVERE] Failed after 131ms
Failed to update packages.
➜  chatgpt_book_code git:(chapter-4) ✗ 
➜  chatgpt_book_code git:(chapter-4) ✗ flutter pub run build_runner build --delete-conflicting-outputs
Deprecated. Use `dart run` instead.
[INFO] Generating build script completed, took 373ms
[INFO] Reading cached asset graph completed, took 124ms
[INFO] Checking for updates since last build completed, took 909ms
[INFO] Running build completed, took 21ms
[INFO] Caching finalized dependency graph completed, took 94ms
[SEVERE] envied_generator:envied on lib/env.dart (cached):

Environment variable not found for field `apiKey`.
package:chatgpt/env.dart:8:16
  ╷
8 │   static const apiKey = _Env.apiKey;
  │                ^^^^^^
  ╵
[SEVERE] Failed after 129ms