Fixed a mistake in the documentation about the Headers.

[rinonb]

A small change in the documentation regarding headers.

The "headers" property was listed as:

headers={{
  Authorization: 'bearer some-token-value',
  'X-Custom-Header': 'some value'
}}

Which makes it look like it's a prop, but in reality, is just a property of the source object.

source={{
  uri: "https://www.example.com/video.mp4",
  headers: {
    Authorization: 'bearer some-token-value',
    'X-Custom-Header': 'some value'
  }
}}

[n1ru4l]

Thank you for your contribution!