Update README.md

maven jar 3.2.3 is ready now
[maven-release-plugin] prepare release v3.2.2
[maven-release-plugin] prepare for next development iteration
Remove gpg pom config, use default.
[maven-release-plugin] prepare release v3.2.3
[maven-release-plugin] prepare for next development iteration
1. Upgrade to slf4j-api-1.7.7 for libs/
2. Add log4j support jars to libs, and project build path.  They are for example running.
3. Add a device example.