Write a function which increments a number at the end of the string, and returns it as a new string. If the string ends with a number, the number must be incremented by 1. If the string does not end with a number the number 1 should be appended to the new string.
If the number has leading zeros the amount of digits should be considered.
abc >>> abc1
abcxyz23 >>> abcxyz24
asd0042 >>> asd0043
asd9 >>> asd10