Document conditions for when to expect a new shaded version

[adamkennedy]

The versions of protobuf supported by protoc-jar and protoc-jar-maven-plugin seem to advance independently of the versions of the protobuf-java-shaded-XXX repos.

It's not clear whether or not it's reasonable or not to expect that protobuf-java-shaded-380 may or should be created, or whether the lack of a particular version is intentional because it can be worked around with some other maven usage pattern.

Would it be possible to add a documentation section to the README.md or similar of this repo (and copy forwards to future repos), which explains the methodology in use here, and if possible demonstrate what a recommended usage of Protobuf 3.8 would look like to achieve shading (if that is the intention).

[os72]

Are you in need of a protobuf-java-shaded-380?

[os72]

FYI, I published protobuf-java-shaded-3-11-1
https://github.com/os72/protobuf-java-shaded-3-11-1