Convert a number to hours and minutes

Write a JavaScript function to convert a given number in minutes to hours and minutes.

Sample Code:

function convertTime(num) {
// Enter your logic here...
}

Examples:

Input: 235
Output: '3:55'
Explanation: 235 is equal to 3 hours and 55 minutes.

Input: 1060
Output: '17:40'
Explanation: 1060 is equal to 17 hours and 40 minutes.