Add coverage badge to Readme

[peterdudfield]

Detailed Description

Add a coverage badge from the unitest to the main Readme.md file

Context

• nice to see what the coverage is like - and for other people to see

[Khushi-agarwal]

@peterdudfield can I work on this issue.

[peterdudfield]

Great stuff @Khushi-agarwal . Let me know if you need anything from me

[peterdudfield]

Hi @Khushi-agarwal, I hope its ok. I went ahead and used codecov for this