Fix Redis Sentinel connection issue by preserving Sentinel Master ID and Hosts in RedisConfig

[cetingokhan]

Summary

This PR addresses two key issues:

Sentinel Connection: Fixes a bug where configuring a [redis-sentinel] URI failed to establish a connection to the Redis Master because the Sentinel Master ID and Host details were lost during configuration parsing.

Build Environment: Updates the [Dockerfile] to use a supported Gradle image, as the previous OpenJDK image is deprecated and was causing build failures.

Changes

Modified [RedisConfig.java]: Updated [redisURIBuilder()] to explicitly check for sentinelMasterId and sentinels in the parsed URI. If present, they are now manually added to the [RedisURI.Builder] to ensure the final URI is correctly configured for Sentinel mode.

Updated [Dockerfile]: Replaced the deprecated openjdk:18-jdk-slim build image with gradle:8.10.0-jdk17. This fixes ./gradlew execution issues and ensures a stable build environment compatible with the project's Java 17 requirement.

Added Unit Test: Added [testRedisSentinelValueConfig] in [StreamSourceConnectorTest.java] to verify that [redis-sentinel] URIs are correctly parsed and that the Master ID and Sentinel hosts are preserved.

Testing

Unit Testing: Verified with the new test case [StreamSourceConnectorTest.testRedisSentinelValueConfig].

Integration Testing: Validated in a local Docker Compose environment with a dedicated Redis Sentinel setup.
Confirmed successful connection for both Sink and Source connectors using [redis-sentinel://] URIs.
Verified password authentication and consumer group functionality with Sentinel.

Build Verification: Confirmed that the project builds successfully with the new Dockerfile configuration.

Related Issue

Fixes [java.lang.IllegalStateException: Cannot build a RedisURI. One of the following must be provided Host, Socket or Sentinel] when using Sentinel and resolves build failures due to deprecated base images.

[cetingokhan]

Hi @jruaux,
I hope you're doing well. I was wondering if there are any plans for an upcoming release soon? Also, I wanted to check if there is anything else I should update or improve in my Pull Request #61 to make it ready for inclusion.

Thanks for maintaining this great project!