• Upgrade to Protobuf 3.16.0 (#97, #101, #107)
• Publish the public runtime API for future compatibility checks (#99)
• URL-encode extensions classpath entries (#102)
• Remove references to JCenter repository (#98, #103)
• Clean up some Gradle config (#104)
• Update dependencies, including protobuf-gradle-plugin to support Gradle 7+ (#106)
• Upgrade Kotlin compilation and runtime dependency to 1.4+ (#109)
• Upgrade Gradle to 7.0.1 (#109)