Addressing deprecations in RestTemplateBuilder

[riccardoforzan]

What's changed?

This PR adds a recipe for replacing some deprecation in RestTemplateBuilder

What's your motivation?

• Addresses part of Recipes to upgrade to Spring Boot 3.4

Anything in particular you'd like reviewers to focus on?

This PR does not address the deprecation of requestFactory that needs to be migrated to requestFactoryBuilder

Checklist

• I've added unit tests to cover both positive and negative cases
• I've read and applied the recipe conventions and best practices
• I've used the IntelliJ IDEA auto-formatter on affected files

[timtebeek]

Thanks for getting this started @riccardoforzan ; Seems like we are nearly there, but perhaps need to start a 3_4 suite of tests, and add the required dependencies there.

rewrite-spring/build.gradle.kts

Line 9 in ba73864

val springBootVersions: List<String> = listOf("1_5", "2_1", "2_2", "2_3", "2_4", "2_5", "2_6", "2_7", "3_0", "3_2", "3_3")

[timtebeek]

Great to see! Thanks for helping out with these RestTemplateBuilder migration steps. 🙏🏻