Converted the default banner image to .webp format.

[DevHrithik]

Pull Request

Related Issues: Converted the default banner image to .webp format.

Fixes #170

Description: I replaced the png file with webp file for the banner image

Checklist:

• [x] I have tested my changes.
• [x] My code follows the project's coding standards.
• [x] I have updated the documentation (if applicable).

Screenshots:

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[ani1609]

@DevHrithik done