Release Apache Iceberg C++ 0.3.0

[zhjwpku]

• Test the revision to be released
• Bump version to 0.2.0
• Prepare RC and create tag by running dev/release/release_rc.sh
• Verify RC by running dev/release/verify_rc.sh
• Send vote email:
• Publish release after the vote passes by running dev/release/release.sh
• Report to ASF: https://reporter.apache.org/addrelease.html?iceberg
• Send announcement email:
• Bump version to 0.4.0

For details of each step, please refer to https://github.com/apache/iceberg-cpp/tree/main/dev/release.