support Project.ListEvents type_in field

[displague]

The GET /projects/{id}/events endpoint supports a path query parameter called type_in.

This field can be seen in use on the Equinix Metal console when filtering events by resource type.

Packngo does not offer a way to provide this value.

Some possibilities:

• ignore the field, defer to resource specific event methods
  client.Devices.ListEvents(), client.Users.ListEvents(), ...

• add the field as an extra ListEvents argument
  client.Projects.ListEvents(project_id, type_in, searchOpts)

• provide a generic map field in ListOptions for additional (unknown) query parameters
  client.Projects.ListEvents(project_id, packngo.SearchOpts{Query:map[string]interface{"type_in":"devices"}) or
  client.Projects.ListEvents(project_id, packngo.SearchOpts{QuerySuffix:"&type_in=devices"})

• add type_in to SearchOpts
  client.Projects.ListEvents(project_id, packngo.SearchOpts{TypeIn:"devices"}

  This allows SearchOpts to act as a grab-bag of documented limited use fields. I would avoid this unless type_in is commonly used or there are other one-off query params like type_in to include in SearchOpts. By assembling these fields in SearchOpts, we are giving up some of our strict type checking and permitted parameter enforcement.

I'd like to understand how common this parameter is or how many other one-off path parameters exist before proceeding. We can look at the api-docs path parameters to determine this (assuming the one-offs are included).