issue 86 - Shield added

[AayushiJapsare15]

What does this PR do?

Shield power up is now added which will provide protection from aliens for 4 secs.

Fixes #86

Type of change

• New feature (non-breaking change which adds functionality)

How should this be tested?

• Catch a shield power-up.

Mandatory Tasks

• Make sure you have self-reviewed the code. A decent size PR without self-review might be rejected.

@YadavAkhileshh, could you kindly add the hacktoberfest-accepted and appropriate level labels to my PR? Thank you!

[github-actions]

Thank you for submitting your pull request! 🙌 We'll review it as soon as possible. In the meantime, please ensure that your changes align with our chaotic CONTRIBUTING.md. If there are any specific instructions or feedback regarding your PR, we'll provide them here. Thanks again for your contribution! 😊

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[github-actions]

🎉🎉 Thank you for your contribution! Your PR #515 has been merged! 🎉🎉

[AayushiJapsare15]

@YadavAkhileshh please add gssoc-ext , hacktoberfest-accepted and appropriate level label.