custom style for header with react LinearGradient

[kunuit]

[peacechen]

Thanks for the PR @kunuit

Please share a screenshot of the intended for this prop and update the Readme detailing how to use it.

It looks like you used an auto-formatter on the file. Please revert the cosmetic changes and only include the relevant functional changes. That makes it easier to see what the changes are. Different people have different formatting settings and that causes too much churn from one person to the next.