Update Readme

[Sapna2001]

Readme can be updated with details of mentors,admins,slack channels and details of gssoc. Please assign me this issue.here.

[kichloo]

@dikshagoyal26 I can work on this issue.

[dikshagoyal26]

@Sapna2001 you can work on this.

[RhuthuHegde]

Can I work on this issue, under gssoc'21?

[Aarti002]

hey @Sapna2001 can i take this issue under gssoc'21

[richakumari19]

I'm a GSSOC'21 participant kindly asssign me this issue. I would love to work in this.

[KajalSinghBAGHEL]

I am GSSOC 21 participant I am a beginner and would like to work on this issue and learn new things, please assign me.