docs: note tested docker-compose version

Also adds a paragraph about recognizing an outdated version in the
troubleshooting section.

Signed-off-by: Hank Donnay <hdonnay@redhat.com>

Documentation/howto/testing.md

@@ -7,7 +7,7 @@ This environment can be used to test and develop Clair's Quay integration.
 
 ### Make
 
-Make is used to stand up the the local dev environment. 
+Make is used to stand up the the local dev environment.
 Make is readily available in just about every package manager you can think of.
 It's very likely your workstation already has make on it.
 
@@ -16,7 +16,7 @@ It's very likely your workstation already has make on it.
 Currently our local dev tooling is supported by docker and docker-compose.
 Podman should work fine since v3.0.
 
-Docker version 19.03.11 and docker-compose version 1.25.4 are confirmed working.
+Docker version 19.03.11 and docker-compose version 1.28.6 are confirmed working.
 Our assumption is most recent versions will not have an issue running the local dev tooling.
 
 See [Install Docker](https://docs.docker.com/get-docker/)
@@ -74,7 +74,7 @@ By default, Quay displays security scanner results on the Tags page of the given
 
 ## Making changes to configuration
 
-You may want to play with either Clair or Quay's configuration. 
+You may want to play with either Clair or Quay's configuration.
 If so, the configuration files can be found inside the repository at `local-dev/quay/config.yaml` and `local-dev/clair/config.yaml`.
 Any changes to the configs will require a restart of the relevant service.
 The quay-specific clair config is autogenerated, see the `Makefile`.
@@ -97,4 +97,7 @@ The second issue you may face is your Docker resource settings maybe too constra
 This is typically seen on Docker4Mac since a VM is used with a specific set of resources configured.
 See [Docker For Mac Manual](https://docs.docker.com/docker-for-mac/) for instructions on how to change these resources.
 
+If `docker-compose` reports errors like `Unsupported config option for services.activemq: 'profiles'`, the `docker-compose` version is too old and you'll need to upgrade.
+Consult the relevant documentation for your environment for instructions.
+
 Lastly, you can view traefik's ui at `localhost:8080/dashboard/`.