docs: add Zulip chat badge to README

[SHITIZ-AGGARWAL]

Description

Fixes #600

Type of Change:

• Documentation

Checklist:

• [x] My PR follows the style guidelines of this project
• [x] I have performed a self-review of my own code or materials
• [x] I have made corresponding changes to the documentation

[codecov-commenter]

Codecov Report

Merging #665 into develop will not change coverage. The diff coverage is n/a.

@@           Coverage Diff            @@
##           develop     #665   +/-   ##
========================================
  Coverage    89.99%   89.99%           
========================================
  Files           49       49           
  Lines         2699     2699           
========================================
  Hits          2429     2429           
  Misses         270      270           

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[SHITIZ-AGGARWAL]

@isabelcosta can you please tell if I did something wrong

[SanketDG]

@SHITIZ-AGGARWAL Can you follow the commit message guidelines?

[SHITIZ-AGGARWAL]

@SanketDG sure ,I will keep that in mind should I commit once again ??

[isabelcosta]

@SHITIZ-AGGARWAL if you can amend the commit and change the message that is good, but if you struggle with it, @SanketDG or I can do that when squashing and merging.

[SHITIZ-AGGARWAL]

@isabelcosta I tried but I am having problem in commit message ,if you could please amend it that would be a great help I am new to open source and git