Bump protobuf-java from 2.6.1 to 3.16.1 in /java#967

dependabot[bot] wants to merge 1 commit intomasterapache/singa:masterfrom

dependabot/maven/java/com.google.protobuf-protobuf-java-3.16.1apache/singa:dependabot/maven/java/com.google.protobuf-protobuf-java-3.16.1Copy head branch name to clipboard