Given an unsorted array of numbers and a target ‘key’, remove all instances of ‘key’ in-place and return the new length of the array.

Input: [3, 2, 3, 6, 3, 10, 9, 3], Key=3 Output: 4 Explanation: The first four elements after removing every 'Key' will be [2, 6, 10, 9].

Input: [2, 11, 2, 2, 1], Key=2 Output: 2 Explanation: The first two elements after removing every 'Key' will be [11, 1].