v0.13.0

What's Changed

• Add clarifying notes to CEL codelab exercise 4 solution. by @copybara-service[bot] in #1595
• Load proto_library and cc_proto_library rules from protobuf and bump minimum version to 28.3 by @copybara-service[bot] in #1597
• Adding the CEL regex extensions by @copybara-service[bot] in #1593
• Adding the decls and checker lib to CEL regex extensions by @copybara-service[bot] in #1600
• Internal Changes by @copybara-service[bot] in #1611
• Sync copybara script changes. by @copybara-service[bot] in #1631
• Bump abseil and protobuf versions. by @copybara-service[bot] in #1632

Full Changelog: v0.12.0...v0.13.0