Releasing PLC4X-Extras

TL/DR

• Update the RELEASE_NOTES
• Check year in NOTICE
• Create release branch:

   ./mvnw -P with-c,with-go,with-java -DbranchName=rel/{current-short-version} release:branch

• Add a new section to the RELEASE_NOTES on develop
• Switch to the release branch and prepare the RELEASE_NOTES
• Prepare the release:

   ./mvnw -P with-c,with-go,with-java release:prepare

• Perform the release:

   ./mvnw release:perform

• Close the staging repo on Nexus
• Stage the release artifacts in SVN
• Vote on the mailing list
• Move RC to the release section of SVN
• Remove old releases in SVN
• Release staging repo on Nexus
• Merge back release version to release branch
• Send announce email