3.0 Hash generated by DigestAuthhenticate::generateResponseHash() does not match $digest['response'] when using PUT

The hash generated by DigestAuthhenticate::generateResponseHash() does not match  $digest['response'] when submitting an existing form.

I can "fix" the issue by changing the following line
```php
$hash = $this->generateResponseHash($digest, $password, $request->env('REQUEST_METHOD'));
```
in
```php
$hash = $this->generateResponseHash($digest, $password, $_SERVER['REQUEST_METHOD']);
```
Adding some debug lines in DigestAuthenticate::getUser() results in following result:
```php
debug($request->env('REQUEST_METHOD'));
debug($_SERVER['REQUEST_METHOD']);
die();
```
```
/src/Auth/DigestAuthenticate.php (line 115)
'PUT'
/src/Auth/DigestAuthenticate.php (line 116)
'POST'
```