Added options to fetch function

[tombroucke]

When running the fetch() function, we can now add options:

fetch(
    'https://httpbin.org/get',
    options: [
        CURLOPT_SSL_VERIFYPEER => false,
        CURLOPT_SSL_VERIFYHOST => false,
        CURLOPT_TIMEOUT => 30,
        ...
    ]
);

• [ ] Bug fix #…?

• [x] New feature?

• [ ] BC breaks?

• [ ] Tests added?

• [x] Docs added?

  Please, regenerate docs by running next command:
  $ php bin/docgen