Issue title: Deprecated warning on PHP 8.1
 Issue body: https://github.com/JackieDo/Laravel-Dotenv-Editor/blob/f93690a80915d51552931d9406d79b312da226b9/src/Jackiedo/DotenvEditor/DotenvReader.php#L138

The line above will return the following warning on PHP 8.1 : 

```
PHP Deprecated:  auto_detect_line_endings is deprecated in {...}/jackiedo/dotenv-editor/src/Jackiedo/DotenvEditor/DotenvReader.php on line 138
```

https://wiki.php.net/rfc/deprecations_php_8_1#auto_detect_line_endings_ini_setting
 Comments: 
 Comment 0: I'm also getting these:

> Deprecation Notice: strlen(): Passing null to parameter #1 ($string) of type string is deprecated in /var/www/html/britishhamper2021/vendor/jackiedo/dotenv-editor/src/Jackiedo/DotenvEditor/DotenvFormatter.php:59
> Deprecation Notice: trim(): Passing null to parameter #1 ($string) of type string is deprecated in /var/www/html/britishhamper2021/vendor/jackiedo/dotenv-editor/src/Jackiedo/DotenvEditor/DotenvFormatter.php:79

For background, see https://php.watch/versions/8.1/internal-func-non-nullable-null-deprecation & https://wiki.php.net/rfc/deprecate_null_to_scalar_internal_arg
 Comment 1: @lcharette, @jontjs:
This issue has been resolved (commit 154228bacd1f3eddc38371cb309c45e0e0d3f071) and included in the [1.2.1](https://github.com/JackieDo/Laravel-Dotenv-Editor/releases/tag/1.2.1) release
{'source': 'GithubIssues', 'repo_name_with_owner': 'JackieDo/Laravel-Dotenv-Editor', 'issue_id': 1091907476, 'repo_stars': 181.0}