Implement Space Replacement Function

# Introduction

In this challenge, we will solve the problem of replacing spaces in a string with "%20". To achieve this, we must implement a function called `replaceSpace` in a file named `replaceSpace.js`. The function will take a string `s` as input and replace every space in the string with "%20". The challenge comes with test cases and length restrictions. It is crucial to note that the filename and function name should not be altered, and the function has to be exported for successful submission.