Merge branch 'dev-support-concurrent-workers' into 'dev'

[cli] add support to spawn multiple workers of the same type

See merge request !437
4 jobs for dev in 54 minutes and 36 seconds (queued for 22 minutes and 19 seconds)
Status Job ID Name Coverage
  Cabal
passed #19188
cabal

00:24:55

 
  Stack
passed #19189
stack

00:03:08

 
  Bench
manual #19190
allowed to fail manual
bench
 
  Test
passed #19191
test

00:26:31