Latest version of com.google.protobuf:protoc
https://javadoc.io/doc/com.google.protobuf/protoc
Current version 2.5.0
https://javadoc.io/doc/com.google.protobuf/protoc/2.5.0
package-list path (used for javadoc generation -link option)
https://javadoc.io/doc/com.google.protobuf/protoc/2.5.0/package-list