More forgiving ignore option

Thanks for this amazing package 🚀
I ran into a problem when I using `--ignore="table1, table2, ...` because of the exploding does not allow whitespace. How about changing that to a more forgiving `preg_split`?

Example:
```
$list = "a, b,c d";

preg_split('/[,\s]+/', $list);

```

This might be implemented in other places as well.

src/OscarAFDev/MigrationsGenerator/MigrateGenerateCommand.php

@@ -396,7 +396,7 @@ protected function getExcludedTables()
 		$excludes = ['migrations'];
 		$ignore = $this->option('ignore');
 		if ( ! empty($ignore)) {
-			return array_merge($excludes, explode(',', $ignore));
+			return array_merge($excludes, preg_split('/[,\s]+/', ignore));
 		}
 
 		return $excludes;