Upgrade server to 1.16.4

Downloading:  https://hub.spigotmc.org/jenkins/job/BuildTools/lastSuccessfulBuild/artifact/target/BuildTools.jar

And then running

```
jstockdi@Bones BuildTools % export MAVEN_OPTS="-Xmx2G"
jstockdi@Bones BuildTools % java -Xmx2G -jar BuildTools.jar
```