Create a function average_temp(s) that accepts a file name s that contains temperature readings. Each line in the file contains
a date followed by 24 hourly temperature readings in a comma-separated-value format, like this example:
2/3/2016,18,17,17,18,20,22,25,30,32,32,32,33,31,28,26,26,25,22,20,20,19,18,18,18
For each line in the file, the function should print out a line containing two items: the date, then comma, then the average temperature on that date, e.g.
3/5/2018, 58.24
3/6/2018, 60.11
3/7/2018, 57.55