EN/Custom Header for HTTP Client

[PiyushSingh-ZS]

Pull Request Template

Description:

• Added support for custom headers for http client
• Closes: #601

Checklist:

• [x] I have formatted my code using goimport and golangci-lint.
• [x] All new code is covered by unit tests.
• [x] This PR does not decrease the overall code coverage.
• [x] I have reviewed the code comments and documentation for clarity.

Thank you for your contribution!