Increase Snake Speed when Eating Food

Fixes issue #2 Increasing the snake speed when eating food

Changes Made:

Modified the JavaScript code to increase the snake's speed by 0.1 units every time it eats food.
Tested the functionality to ensure that the snake's speed increases appropriately after consuming food.

video attached is increasing the speed by 1 every time for the convenience, in the pr it is increasing by 0.1 only

iiitl / snake-game-js