Merge JSON 2.7.2

https://github.com/flori/json/commit/a1af7a308c

(https://github.com/flori/json/pull/557)

* RDoc for additions

* Update lib/json/add/time.rb

Co-authored-by: Hiroshi SHIBATA <hsbt@ruby-lang.org>

---------

https://github.com/flori/json/commit/3f2efd60f7

Co-authored-by: Hiroshi SHIBATA <hsbt@ruby-lang.org>

https://github.com/flori/json/commit/41c2712a3b

https://github.com/flori/json/commit/936f280f9f

Fix: https://github.com/flori/json/issues/553

We can never add keyword arguments to `dump` otherwise
existing code using unenclosed hash will break.

https://github.com/flori/json/commit/8e0076a3f2

  > https://github.com/flori/json/pull/525
  > Rename escape_slash in script_safe and also escape E+2028 and E+2029

  Co-authored-by: Jean Boussier <jean.boussier@gmail.com>

  > https://github.com/flori/json/pull/454
  > Remove unnecessary initialization of create_id in JSON.parse()

  Co-authored-by: Watson <watson1978@gmail.com>

It is rather common to directly interpolate JSON string inside
<script> tags in HTML as to provide configuration or parameters to a
script.

However this may lead to XSS vulnerabilities, to prevent that 3
characters need to be escaped:

  - `/` (forward slash)
  - `U+2028` (LINE SEPARATOR)
  - `U+2029` (PARAGRAPH SEPARATOR)

The forward slash need to be escaped to prevent closing the script
tag early, and the other two are valid JSON but invalid Javascript
and can be used to break JS parsing.

Given that the intent of escaping forward slash is the same than escaping
U+2028 and U+2029, I chos to rename and repurpose the existing `escape_slash`
option.

https://github.com/flori/json/commit/ca546128f2

https://github.com/flori/json/commit/ec47749b53