Add options overload parameter to sendFile function

[mav-rik]

Prerequisites

• I have written a descriptive issue title
• I have searched existing issues to ensure the feature has not already been requested

🚀 Feature Proposal

Sometimes it's required to control cache headers more granularly, so it would be nice to have an option to overwrite the options while calling sendFile (just like it's already done for download).

Motivation

No response

Example

fastify.get('/path', function (req, reply) {
  return reply.sendFile('some-file.js', { maxAge: 0 })
})

fastify.get('/path/custom', function (req, reply) {
  return reply.sendFile('some-file.js', 'custom-filename.js', { maxAge: 0 })
})

[mcollina]

Would you like to send a Pull Request to address this issue? Remember to add unit tests.

[mav-rik]

Would you like to send a Pull Request to address this issue? Remember to add unit tests.

done, new pull request #239