nats/v0.25.0

Overview

A small release that allows client compile on MIPS and PowerPC architectures.
It also adds the legacy notice and examples how to use async client in sync environments.

What's Changed

• Add sync client legacy notice
• Updates Message Metadata docs
• Allow client to compile on MIPS and PowerPC by @protochron in #1210
• Update NKEYS to v0.4.1

Thank you @protochron for your contribution!