Write an efficient algorithm that searches for a value `target` in an `m x n` integer matrix `matrix`. This matrix has the following properties:

- Integers in each row are sorted from left to right.
- The first integer of each row is greater than the last integer of the previous row.

Example 1:

    Input: matrix = [[1,3,5,7],[10,11,16,20],[23,30,34,60]], target = 3
    Output: true

Example 2:

    Input: matrix = [[1,3,5,7],[10,11,16,20],[23,30,34,60]], target = 13
    Output: false

Constraints:

- `m == matrix.length`
- `n == matrix[i].length`
- `1 <= m, n <= 100`
- `-104 <= matrix[i][j], target <= 104`