Uffizzi Preview Workflow Improvements

* Add an explicit newline before the end of the event JSON blob.
* Include conditions to skip without successful build workflow.
* Upload event payload file directly from runner context.

Signed-off-by: Adam Vollrath <adam.d.vollrath@gmail.com>

.github/workflows/uffizzi-build.yml

@@ -89,16 +89,11 @@ jobs:
           name: preview-spec
           path: docker-compose.rendered.yml
           retention-days: 2
-      - name: Serialize PR Event to File
-        run: |
-          cat << EOF > event.json
-          ${{ toJSON(github.event) }}
-          EOF
       - name: Upload PR Event as Artifact
         uses: actions/upload-artifact@v3
         with:
           name: preview-spec
-          path: event.json
+          path: ${{ github.event_path }}
           retention-days: 2
 
   delete-preview:
@@ -107,14 +102,9 @@ jobs:
     if: ${{ github.event.action == 'closed' }}
     steps:
       # If this PR is closing, we will not render a compose file nor pass it to the next workflow.
-      - name: Serialize PR Event to File
-        run: |
-          cat << EOF > event.json
-          ${{ toJSON(github.event) }}
-          EOF
       - name: Upload PR Event as Artifact
         uses: actions/upload-artifact@v3
         with:
           name: preview-spec
-          path: event.json
+          path: ${{ github.event_path }}
           retention-days: 2

.github/workflows/uffizzi-preview.yaml

@@ -11,6 +11,7 @@ jobs:
   cache-compose-file:
     name: Cache Compose File
     runs-on: ubuntu-latest
+    if: ${{ github.event.workflow_run.conclusion == 'success' }}
     outputs:
       compose-file-cache-key: ${{ env.COMPOSE_FILE_HASH }}
       pr-number: ${{ env.PR_NUMBER }}
@@ -47,7 +48,7 @@ jobs:
         run: |
           echo 'EVENT_JSON<<EOF' >> $GITHUB_ENV
           cat event.json >> $GITHUB_ENV
-          echo 'EOF' >> $GITHUB_ENV
+          echo -e '\nEOF' >> $GITHUB_ENV
 
       - name: Hash Rendered Compose File
         id: hash
@@ -77,6 +78,7 @@ jobs:
     name: Use Remote Workflow to Preview on Uffizzi
     needs:
       - cache-compose-file
+    if: ${{ github.event.workflow_run.conclusion == 'success' }}
     uses: UffizziCloud/preview-action/.github/workflows/reusable.yaml@v2
     with:
       # If this workflow was triggered by a PR close event, cache-key will be an empty string