Complete the implementation of max_repeat_counts, which takes a non-empty list and returns a dictionary containing a key for each element in the list, with a value corresponding to the maximum number of times the element repeats (in succession).

E.g., max_repeat_counts([1, 2, 2, 2, 2]) returns {1: 1, 2: 4}. E.g., max_repeat_counts([3, 3, 4, 4, 3, 4, 4, 4]) returns {3: 2, 4: 3}.