[Java][RestEasy] Upgrade to resteasy-jackson2-provider

[iamolivinius]

PR checklist

• Read the contribution guidelines.
• Ran the shell script under ./bin/ to update Petstore sample so that CIs can verify the change. (For instance, only need to run ./bin/{LANG}-petstore.sh and ./bin/security/{LANG}-petstore.sh if updating the {LANG} (e.g. php, ruby, python, etc) code generator or {LANG} client's mustache templates). Windows batch files can be found in .\bin\windows\.
• Filed the PR against the correct branch: 3.0.0 branch for changes related to OpenAPI spec 3.0. Default: master.
• Copied the technical committee to review the pull request if your PR is targeting a particular programming language.

Description of the PR

Since jackson-2.6.4 is used the dependency resteasy-jackson2-provider should be used to reflect that.

[iamolivinius]

@bbdouglas (2017/07) @JFCote (2017/08) @sreeshas (2017/08) @jfiala (2017/08) @lukoyanov (2017/09) @cbornet (2017/09)

[wing328]

@iamolivinius thanks for the PR. Can you please also update build.gradle as well?

Then please run ./bin/java-petstore-resteasy-all.sh or corresponding batch files under .\bin\windows\ to update Petstore samples so that the CI can verify the change.

[iamolivinius]

@wing328 the build.gradle doesn't include the same dependency.

[wing328]

@wing328the build.gradle doesn't include the same dependency.

The build.gradle in the latest master is broken for RestEasy. I'll create another task to track it.

[wing328]

FYI. I've reopened #5925 to track the Gradle build issue.