Update install.sh (#3270)
Optimization Code
1. Use #!/usr/bin/env bash instead of #!/bin/bash to make the script more portable.
2. Use rm -rf instead of rm -r to remove directories recursively.
Co-authored-by: Logan Adams <114770087+loadams@users.noreply.github.com>
Co-authored-by: Olatunji Ruwase <olruwase@microsoft.com>
