#893 Disable Jackson ObjectMapper FAIL_ON_UNKNOWN_PROPERTIES Deserialization Feature by default

[amiriahmad72]

In order to disable Jackson ObjectMapper FAIL_ON_UNKNOWN_PROPERTIES Deserialization Feature by default , Edit static newObjectMapper method of JacksonSerializer:

static ObjectMapper newObjectMapper() {
    return new ObjectMapper()
            .registerModule(MODULE)
            .configure(JsonParser.Feature.STRICT_DUPLICATE_DETECTION, true) // https://github.com/jwtk/jjwt/issues/877
            .configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false); // https://github.com/jwtk/jjwt/issues/893
}

Also add specific test with json which has unknown field and must seserialize to custom data type.

This PR fixs #893

Note:
I close #894 PR and reopen this PR, because it has confilict with synchronous and same changes in #895 PR of @lhazlewood

[amiriahmad72]

Hi @lhazlewood
Could you please check this PR?

[lhazlewood]

@amiriahmad72 sorry about the delay, I should be able to review it properly today.

[amiriahmad72]

@lhazlewood Thank you for your review. I've updated the JavaDoc.