Support bracket-style OpenAPI 3 query params

[ydah]

Fixes: #327

This fixes OpenAPI 3 request validation for query parameters declared with bracket notation, for example:

- in: query
  name: filter[slug]
  required: true
  schema:
    type: string

Rack parses a request like ?filter[slug]=/test into a nested hash:

{ "filter" => { "slug" => "/test" } }

Before this change, Committee validated against the literal parameter name only, so the request was rejected as:

missing required parameters: filter[slug]

This change normalizes Rack-style nested query hashes into bracket notation before OpenAPI 3 parameter validation/deserialization when the schema expects bracket-style names.

[geemus]

Oops, sorry for the delay. I saw the draft, but missed it when you marked it ready for review.

lgtm

[ydah]

Thank you!