This commit introduces a new module `feign-jackson3` that provides support for Jackson 3.x,
alongside the existing `feign-jackson` module which continues to support Jackson 2.x.

## Changes

### Module Creation
- Created new `jackson3` module based on `feign-jackson`
- Added module to parent POM

### Jackson 3 Migration
- **Dependency**: Upgraded to Jackson 3.0.2 (`tools.jackson.core:jackson-databind`)
- **Package changes**: Migrated from `com.fasterxml.jackson.*` to `tools.jackson.*`
  - Exception: `com.fasterxml.jackson.annotation` remains unchanged (as per Jackson 3 spec)
- **Maven coordinates**: Updated groupId from `com.fasterxml.jackson.core` to `tools.jackson.core`

### API Changes
- **Immutable ObjectMapper**: Replaced direct `ObjectMapper` instantiation with `JsonMapper.builder()`
  - All configuration now done via builder pattern
- **Exception handling**:
  - Jackson 3 uses `JacksonException` (unchecked) instead of `IOException` (checked)
  - Updated catch blocks to handle `JacksonException` and extract `IOException` from cause when needed
- **Module type**: Changed from `Module` to `JacksonModule`

### Configuration
- **Default settings**: Respects Jackson 3 defaults (improved security)
  - `FAIL_ON_TRAILING_TOKENS` enabled by default (new in Jackson 3)
  - Explicitly disabled for `Jackson3IteratorDecoder` only (required for streaming array elements)
- **Java version**: Minimum Java 17 required (Jackson 3 baseline)

### Classes
- `Jackson3Decoder`: Standard JSON decoder for Jackson 3
- `Jackson3Encoder`: Standard JSON encoder for Jackson 3
- `Jackson3IteratorDecoder`: Streaming iterator decoder for large JSON arrays

### Tests
- Migrated all tests from `feign-jackson`
- Updated to use Jackson 3 APIs (`tools.jackson.*` packages)
- Updated method names for Jackson 3 API changes (e.g., `getCurrentName()` → `currentName()`)
- All tests passing ✅

## Migration Notes

Users can migrate from `feign-jackson` to `feign-jackson3` by:
1. Updating dependency to `feign-jackson3`
2. Changing imports from `feign.jackson.*` to `feign.jackson3.*`
3. Ensuring Java 17+ is available

Both modules can coexist in the same project if needed.

## References
- [Jackson 3 Migration Guide](https://github.com/FasterXML/jackson/blob/main/jackson3/MIGRATING_TO_JACKSON_3.md)
- [Jackson 3.0 Release Notes](https://github.com/FasterXML/jackson/wiki/Jackson-Release-3.0)

Signed-off-by: Marvin Froeder <[email protected]>

# Conflicts:
#	pom.xml

…dules

Signed-off-by: Marvin Froeder <[email protected]>