If .env contains PORT and SOMETHINGELSE_PORT, then PORT is not generated as type or example

I have a .env file with 
```
# .env
...
REDIS_PORT=12345
PORT=6789
...
```
but when i run gen-env-types, I get 
```
// env.d.ts
declare namespace NodeJS {
  interface ProcessEnv {
    ...
    REDIS_PORT: string;
    // no PORT
    ...
  }
}
```
and .env.example
```
# .env.example
...
REDIS_PORT=
# no PORT=
...
```