Update gocd-agent package version to 16.6.0-3590 including new sha. Modify heapSize
and maxMemory mkOption to accurately reflect their intended purpose of configuring
initial java heap sizes.
GoCD is an open source continuous delivery server specializing in advanced workflow
modeling and visualization. Update maintainers list to include swarren83. Update
module list to include gocd agent and server module. Update packages list to include
gocd agent and server package. Update version, revision and checksum for GoCD
release 16.5.0.
