www/ruby-rest-client: update to 2.1.0

Update to ruby-rest-client to 2.1.0.

# 2.1.0

- Add a dependency on http-accept for parsing Content-Type charset headers.
  This works around a bad memory leak introduced in MRI Ruby 2.4.0 and fixed in
  Ruby 2.4.2. (#615)
- Use mime/types/columnar from mime-types 2.6.1+, which is leaner in memory
  usage than the older storage model of mime-types. (#393)
- Add `:log` option to individual requests. This allows users to set a log on a
  per-request / per-resource basis instead of the kludgy global log. (#538)
- Log request duration by tracking request start and end times. Make
  `log_response` a method on the Response object, and ensure the `size` method
  works on RawResponse objects. (#126)
  - `# => 200 OK | text/html 1270 bytes, 0.08s`
  - Also add a new `:stream_log_percent` parameter, which is applicable only
    when `:raw_response => true` is set. This causes progress logs to be
    emitted only on every N% (default 10%) of the total download size rather
    than on every chunk.
- Drop custom handling of compression and use built-in Net::HTTP support for
  supported Content-Encodings like gzip and deflate. Don't set any explicit
  `Accept-Encoding` header, rely instead on Net::HTTP defaults. (#597)
  - Note: this changes behavior for compressed responses when using
    `:raw_response => true`. Previously the raw response would not have been
    uncompressed by rest-client, but now Net::HTTP will uncompress it.
- The previous fix to avoid having Netrc username/password override an
  Authorization header was case-sensitive and incomplete. Fix this by
  respecting existing Authorization headers, regardless of letter case. (#550)
- Handle ParamsArray payloads. Previously, rest-client would silently drop a
  ParamsArray passed as the payload. Instead, automatically use
  Payload::Multipart if the ParamsArray contains a file handle, or use
  Payload::UrlEncoded if it doesn't. (#508)
- Gracefully handle Payload objects (Payload::Base or subclasses) that are
  passed as a payload argument. Previously, `Payload.generate` would wrap a
  Payload object in Payload::Streamed, creating a pointlessly nested payload.
  Also add a `closed?` method to Payload objects, and don't error in
  `short_inspect` if `size` returns nil. (#603)
- Test with an image in the public domain to avoid licensing complexity. (#607)


(taca)