Update CI workflows to use GraalVM and add native image build step

[regisx001]

This pull request updates the CI/CD workflows to use GraalVM for building native images, in addition to the existing JAR builds. The workflows now set up GraalVM instead of Temurin, add a native image build step, and update release instructions and artifacts to include the native binary.

CI/CD Workflow Updates:

• Updated both .github/workflows/maven.yml and .github/workflows/release.yml to use actions/checkout@v4 and replace the setup-java action with graalvm/setup-graalvm@v1, configuring the build environment for GraalVM and native image support. [1] [2]
• Added a step in both workflows to build a native executable using mvn -Pnative native:compile. [1] [2]

Release Process Improvements:

• Updated the release workflow to upload the native binary (target/minigit) alongside the JAR file in the release assets.
• Improved the release notes to include installation instructions for both the native binary and the JAR file, making it easier for users to choose the appropriate format.