add support for the showCommonExtensions configuration option of swagger-ui

[guyv]

• What version of the library are you using?
  2.9.0

What kind of issue is this?

• Feature Request.
  In version 3.14.0 of swagger-ui, a new configuration option was added, called showCommonExtensions (https://github.com/swagger-api/swagger-ui/blob/master/docs/usage/configuration.md). This allows formats of query parameters to be shown (formats of query parameters are not shown swagger-api/swagger-ui#4231 and Add option to show common query parameters swagger-api/swagger-ui#4245).
  In version 2.9.0 swagger-ui was bumped to 3.14 (949fb06), however, no support was added for this new property...

[dilipkrish]

This is fixed via #2973