`libprotoc` is outdated

[fandreuz]

I'd like to use otel/build-protobuf to build opentelemetry-proto. I noticed the libprotoc bundled inside the image is more than two years old (3.21.6). I think this comes from the outdated gRPC version, which is also more than two years old.

This is a problem in Java because due to protocolbuffers/protobuf#19540 I'm forced to use an outdated Protobuf runtime JAR, which comes with its own set of problems:

WARNING: Vulnerable protobuf generated type in use: io.opentelemetry.proto.profiles.v1development.ProfilesDictionary
As of 2022/09/29 (release 21.7) makeExtensionsImmutable should not be called from protobuf gencode. 
If you are seeing this message, your gencode is vulnerable to a denial of service attack. You should 
regenerate your code using protobuf 25.6 or later

I know I could just use another image, or protoc directly, but I'd like to raise the discussion in the meantime. Is there any blocker?