1603 - Unknown Concurrency Group '%s'.

Description
Concurrency Groups must be defined in Settings() before being referenced by build steps using them.
Example
Config:
Exec() { .ConcurrencyGroupName = 'deploy' .ExecExecutable = 'deploy.exe' .ExecOutput = 'deploy.log' }
Output:
C:\Test\fbuild.bff(1,1): FASTBuild Error #1603 - Exec() - Unknown Concurrency Group 'deploy'. Exec() ^ \--here
Fix:
Settings { .DeployGroup = [ .ConcurrencyGroupName = 'deploy' .ConcurrencyJobLimit = 1 ] .ConcurrencyGroups = { .DeployGroup } } Exec() { .ConcurrencyGroupName = 'deploy' .ExecExecutable = 'deploy.exe' .ExecOutput = 'deploy.log' }