SqlServerAdapter::getColumns returns associative array

[MasterOdin]

The SqlServerAdapter::getColumns function returns an associative array of columns, where the keys are column names. All other adapters return a numeric array which is also expressed by our AdapterInterface:

phinx/src/Phinx/Db/Adapter/AdapterInterface.php

Lines 426 to 432 in 8270c6e

	/**
	* Returns table columns
	*
	* @param string $tableName Table name
	* @return \Phinx\Db\Table\Column[]
	*/
	public function getColumns(string $tableName): array;

The SqlServerAdapter::getColumns method should be changed to return numeric array. As this is public facing functionality, this will require a major release.