Add date and time format support to mocks

[penx]

This can be done fairly easily by upgrading to a new RC of json-schema-faker once the following PR has been included in a release:

json-schema-faker/json-schema-faker#360

(date and time are listed as OAS Primitive data types)

[penx]

0.5.0-rc13 is out with date and time support, PR raised: #174