Added the CPP project

[akshitagupta15june]

Please confirm this pull request meets the following requirements:

• [y] I followed the contributing guidelines: https://github.com/github/india/blob/main/CONTRIBUTING.md.

Which change are you proposing?

• [y] Adding/updating open source project/s
• [y] Adding/updating maintainer/s

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Adding/updating open source project/s

• [y] The project was built in or receives significant contributions from India
• [y] The project has at least 100 stargazers

Why should this open source project be featured?

In the CPP project, you can find all the programming solutions to all the interview questions, which is a very useful resource for competitive programmers. Contributed by more than 350+

Adding/updating maintainer/s

• [y] Maintainer's location on their GitHub profile indicates as India
• [y] Maintainer has approved this PR to be included on the website

What open source project/s does the individual maintain?

https://github.com/akshitagit/CPP

Something that does not neatly fit into the binary options above

• [y] My suggested edits are not about an existing page, or at least not a single one

I have made changes on maintainers.yml file by adding my github handle as well as I have updated projects following the contributing guideline.

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Please note: we will close your PR without comment if you do not check the boxes above and provide ALL requested information.