add scroll to top button

[iamharshitpandeyy]

Related Issue

• Info about the related issue

Closes: #16

Describe the changes you've made

I make an Scroll to top button which help user to scroll top.

Type of change

What sort of change have you made:

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Code style update (formatting, local variables)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Mention any unusual behaviour of your code (Write NA if not)

Any unusual behaviour of your code

Checklist:

• My code follows the guidelines of this project.
• I have performed a self-review of my own code.
• I have commented my code, particularly wherever it was hard to understand.
• My changes generate no new warnings.
• Any dependent changes have been merged and published in downstream modules.

Which Program are you part of?

• DCP21
• Any other

Additional Info (optional)

Any additional information you want to give