adding deprecated function to BaseSchema

[victortosts]

Adding support to deprecated values.

Reference:

The value of this keyword MUST be a boolean. When multiple occurrences of this keyword are applicable to a single sub-instance, applications SHOULD consider the instance location to be deprecated if any occurrence specifies a true value.

If "deprecated" has a value of boolean true, it indicates that applications SHOULD refrain from usage of the declared property. It MAY mean the property is going to be removed in the future.

A root schema containing "deprecated" with a value of true indicates that the entire resource being described MAY be removed in the future.

When the "deprecated" keyword is applied to an item in an array by means of "items", if "items" is a single schema, the deprecation relates to the whole array, while if "items" is an array of schemas, the deprecation relates to the corrosponding item according to the subschemas position.

Omitting this keyword has the same behavior as a value of false.

Checklist

• run npm run test and npm run benchmark
• tests and/or benchmarks are included
• documentation is changed or added
• commit message and code follows the Developer's Certification of Origin
  and the Code of conduct

[coveralls]

Pull Request Test Coverage Report for Build 1685932661

• 0 of 5 (100.0%) changed or added relevant lines in 3 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.005%) to 99.575%

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Totals
Change from base Build 1683904512:	0.005%
Covered Lines:	426
Relevant Lines:	426

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💛 - Coveralls

[coveralls]

Pull Request Test Coverage Report for Build 1685932661

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

• For more information on this, see Tracking coverage changes with pull request builds.
• To avoid this issue with future PRs, see these Recommended CI Configurations.
• For a quick fix, rebase this PR at GitHub. Your next report should be accurate.

Details

• 5 of 5 (100.0%) changed or added relevant lines in 3 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.005%) to 99.575%

---

Totals
Change from base Build 1683904512:	0.005%
Covered Lines:	426
Relevant Lines:	426

---

💛 - Coveralls

[aboutlo]

hey @victortostes-hotmart thank you for this. it looks nice!

You need to add the typescript types too here:
https://github.com/fastify/fluent-json-schema/blob/master/src/FluentJSONSchema.d.ts

and check that it compiles correctly here:
https://github.com/fastify/fluent-json-schema/blob/master/src/types/index.ts

[victortosts]

@aboutlo let me know if still something missing 😄