Add composer.json file

Added composer.json file. Please review.
Thanks!

Hiiee @Andrii, Your composer.json file looks good, but there are a couple of optional additions you might consider.
"require": {
"drupal/core": "^9"
}
Drupal 8/9 modules generally follow PSR-4 autoloading standards. You can configure autoload settings in your composer.json file. For example:

"autoload": {
"psr-4": {
"Drupal\\taxonomy_protect\\": "src/"
}
}

But still good to go