Need to release officially

[soharang]

Problem

• Its latest release is v0.20.0 which was released about a year ago.
• By the way, the tag for this repository has v0.31.0 as the latest one which was released 2 months ago.

Solution

• hedera-protobufs should release the latest one officially.
• And then hedera-protobufs-[language] repositories should synchronize with it. (e.g. hedera-protobufs-swift, hedera-protobufs-java)

Alternatives

[jsync-swirlds]

Stale. Please reopen if still needed.