Fix #4 GitHub icon align-middle in index.html

[ArushiSingh99]

Description

I have added the github icon to the center-bottom of the sidebar

Fixes #4

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

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
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• Any dependent changes have been merged and published in downstream modules
• I have added all the three reviewers: @vinitshahdeo, @Kashish121 & @ishika1727