(maint) Clarify inventory, ssh key file in acceptance.yml

Just notes that the files were generated as part of the nested_vms
action step.

Author: jpartlow

.github/workflows/acceptance.yaml

@@ -107,19 +107,21 @@ jobs:
         working-directory: kvm_automation_tooling
         env:
           HOSTS_YAML: ${{ github.workspace }}/acceptance/hosts.yaml
+          # Generated by the nested_vms action.
+          INVENTORY: terraform/instances/inventory.test.yaml
         run: |-
           bundle exec bolt plan run \
             kvm_automation_tooling::dev::generate_beaker_hosts_file \
-            --inventory terraform/instances/inventory.*.yaml \
+            --inventory "${INVENTORY}" \
             hosts_yaml="${HOSTS_YAML}"
       - name: Run Beaker
         working-directory: acceptance
+        env:
+          # Generated by the nested_vms action.
+          SSH_KEY: ~/.ssh/ssh-id-test
         run: |-
-          # TODO The ssh keyfile here is from the kvm_automation_tooling
-          # action...this should be cleaned up to be more discoverable
-          # or supplied as an input perhaps.
           bundle exec beaker init --hosts hosts.yaml \
-            --preserve-hosts always --keyfile ~/.ssh/ssh-id-test \
+            --preserve-hosts always --keyfile "${SSH_KEY}" \
             --pre-suite pre-suite/configure_type_defaults.rb \
             --tests tests
           # The provision step is still needed here, see notes in the