chore(ci): Add triggerable workflow to CircleCI

Author: effigies

.circleci/config.yml

@@ -92,6 +92,19 @@ aliases:
 - &src "/tmp/src/petprep"
 orbs:
   docker: circleci/docker@2.1.4
+parameters:
+  GHA_Actor:
+    type: string
+    default: ""
+  GHA_Action:
+    type: string
+    default: ""
+  GHA_Event:
+    type: string
+    default: ""
+  GHA_Meta:
+    type: string
+    default: ""
 
 jobs:
   build_clean:
@@ -428,6 +441,25 @@ jobs:
     steps:
     - run: echo Deploying!
 
+  pull_image:
+    <<: *machine_defaults
+    environment:
+      GHA_Actor: << pipeline.parameters.GHA_Actor >>
+      GHA_Event: << pipeline.parameters.GHA_Event >>
+      GHA_Action: << pipeline.parameters.GHA_Action >>
+      GHA_Meta: << pipeline.parameters.GHA_Meta >>
+      REVISION: << pipeline.git.revision >>
+    steps:
+      - checkout
+      - run:
+          name: Print parameters
+          command: |
+            echo $GHA_Actor
+            echo $GHA_Event
+            echo $GHA_Action
+            echo $GHA_Meta
+            echo $REVISION
+
 workflows:
   version: 2
   build_from_scratch:
@@ -444,6 +476,11 @@ workflows:
         context:
         - nipreps-common
 
+  github:
+    when: << pipeline.parameters.GHA_Action >>
+    jobs:
+    - pull_image
+
   build_test_deploy:
     jobs:
     - build: