fix: network_bandwidth for mac

[shubhamku044]

What

What does this pull request accomplish?

• Finished item
• Item in progress
• Fixes [BUG]: Not getting network bandwidth in my mac m1 air #1

How

What code changes were made to accomplish it?

in network_bandwidth.sh file, I made a check whether uname -s is Darwin or Linux. then I added extra lines inside a if else block for Darwin

Why

• I want to fix the issue # (issue)
• I want to add a new feature
• I want to improve the documentation
• I want to fix the tests

Screenshots (If applicable)

Notes

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• New and existing unit tests pass locally with my changes

[2KAbhishek]

Hardcoding the network name doesn't feel like a good idea, we can use network name passed in as an option for better usability

[shubhamku044]

so I thought that in mac or any laptop, people mostly use wifi to connect to the internet, and this en0 is the wifi. But, I will change it.

[2KAbhishek]

I'm merging this in, will add the name option and docs

[shubhamku044]

Okay

[2KAbhishek]

thanks @shubhamku044
will merge this in after the comments have been resolved