How to insert new key value pair inside a multidimensional associative array in PHP

To insert new key value pair inside a multidimensional associative array in PHP
Here am going to explain in details
We have a sample array we need to add Version4 and its value inside the array

$list_array = array( 
            0 => array (
               "Version1" => 2016,
               "Version2" => 2017,	
               "Version3" => 2018
            ),
            
            1 => array (
               "Version1" => 2016,
               "Version2" => 2017,	
               "Version3" => 2018
            )
         );

Here am using for each mange that

 foreach($list_array as $key=>$valuue)
	 {
	  $list[$key]=$listvalue;
	  $list[$key]['Version4']= 2019;
	 }
       print_r($list);

Result

 
array( 
            0 => array (
               "Version1" => 2016,
               "Version2" => 2017,	
               "Version3" => 2018,
               "Version4" => 2019
          
              
            ),
            
            1 => array (
               "Version1" => 2016,
               "Version2" => 2017,	
               "Version3" => 2018,
               "Version4" => 2019
            )
         );