[OPS-547] Don't allow release and snapshot workflows to run concurrently

[alourie]

Description

We had a couple of releases fail due to the snapshot and the release workflows running at the same time and messing with the git tree. This change groups the snapshot and release workflows into the same concurrency group, which only allows 1 workflow to execute at a time, placing another into a PENDING state while waiting for another workflow to finalise. The following is the type of message the waiting workflow (in this case, a release workflow) will get:

[ryanjcoleman]

Task linked: OPS-547 Don't allow snapshot and release actions to run at the same time

[alourie]

eh, this sneaked in after playing with clearer error messages. I bet no one will notice.

[charlta]

question: Won't this still have the same problem?

t0: kick off snapshot with hash 1
t1: kick off release with hash 1 (paused)
t2: snapshot finished and updates main with release info (hash 2)
t2': resume release action via concurrency group, still pinned to hash 1
t3: release if pushed to maven, but fails to merge back to main due to conflict (with hash 2)

[alourie]

question: Won't this still have the same problem?

t0: kick off snapshot with hash 1 t1: kick off release with hash 1 (paused) t2: snapshot finished and updates main with release info (hash 2) t2': resume release action via concurrency group, still pinned to hash 1 t3: release if pushed to maven, but fails to merge back to main due to conflict (with hash 2)

That's a fair point, I'll run the tests to validate.

[alourie]

@charlta tested, you're correct. Need to come up with something else.