Attempt to fix oci-build-task config

See gh-24197

Author: philwebb

ci/pipeline.yml

@@ -214,16 +214,22 @@ jobs:
     - task: build-ci-image
       privileged: true
       file: git-repo/ci/tasks/build-ci-image.yml
+      output_mapping:
+        image: ci-image-name
       vars:
         ci-image-name: ci-image
     - task: build-ci-image-jdk11
       privileged: true
       file: git-repo/ci/tasks/build-ci-image.yml
+      output_mapping:
+        image: ci-image-jdk11
       vars:
         ci-image-name: ci-image-jdk11
     - task: build-ci-image-jdk15
       privileged: true
       file: git-repo/ci/tasks/build-ci-image.yml
+      output_mapping:
+        image: ci-image-jdk15
       vars:
         ci-image-name: ci-image-jdk15
   - in_parallel:

ci/tasks/build-ci-image.yml

@@ -8,7 +8,6 @@ inputs:
 - name: ci-images-git-repo
 outputs:
 - name: image
-output_mapping: {image: ((ci-image-name))}
 caches:
 - path: ci-image-cache
 params: