Made navbar sticky on Tablet and Mobile

[ZaidKhan2002]

What is the change?

Made navbar sticky on Tablet and Mobile

Related issue?

closes: #48

Checklist:

Before you create this PR, confirm all the requirements listed below by checking the checkboxes [x]:

• [x] I have followed the Code of Conduct.
• [x] I have checked there aren't other open Pull Requests for the same update/change.
• [x] I have you tested the code before submission.
• [x] I have commented my code, particularly in hard-to-understand areas.
• [x] My changes generates no new warnings.
• [x] I'm Hacktoberfest'21 contributor.

Screenshots (if any)

[ZaidKhan2002]

@Chaitalishetty I posted issue for making navbar sticky so should I make navbar responsive with toggle switch or is there any issue with sticky part ?

[Chaitalishetty]

@ZaidKhan2002 Oh sorry my bad .