Allowing custom http method names

Changes

• It is now possible to set the http method of your source()

<!-- +page.svelte -->
<script>
  import { source } from 'sveltekit-sse'
  const connection = source('/issue-55/events', {
    options: {
      method: 'GET',  // The default is POST.
    },
  })
  const message = connection.select('message')
</script>

<h3>{$message}</h3>

import { produce } from 'sveltekit-sse'
import { delay } from '$lib/delay.js'

export async function GET() { // Then you can use GET here.
  return produce(async function start({ emit }) {
    while (true) {
      const { error } = emit('message', `${Date.now()}`)
      if (error) {
        return
      }
      await delay(1000)
    }
  })
}