Fix multiline GitHub output and add dep report steps (DataDog#22929)

Author: AAraKKe

.github/workflows/update-dependencies.yml

@@ -38,12 +38,27 @@ jobs:
     - name: Update dependencies
       run: |-
         ddev dep updates --sync --report /tmp/dep-report.md --report-type markdown
+    - name: Check dependency report
+      id: dep-report-check
+      run: |-
+        if [ -f /tmp/dep-report.md ]; then
+          echo "exists=true" >> "$GITHUB_OUTPUT"
+        else
+          echo "exists=false" >> "$GITHUB_OUTPUT"
+        fi
+    - name: Print dependency report
+      if: steps.dep-report-check.outputs.exists == 'true'
+      run: cat /tmp/dep-report.md
     - name: Read dependency report
       id: dep-summary
+      if: steps.dep-report-check.outputs.exists == 'true'
       run: |-
-        echo "summary<<EOF" >> "$GITHUB_OUTPUT"
-        cat /tmp/dep-report.md >> "$GITHUB_OUTPUT"
-        echo "EOF" >> "$GITHUB_OUTPUT"
+        delimiter="$(openssl rand -hex 16)"
+        {
+          echo "summary<<${delimiter}"
+          cat /tmp/dep-report.md
+          echo "${delimiter}"
+        } >> "$GITHUB_OUTPUT"
     - name: Update licenses
       run: |-
         ddev validate licenses --sync
@@ -68,7 +83,7 @@ jobs:
           ### What does this PR do?
           Update the dependencies
 
-          ${{ steps.dep-summary.outputs.summary }}
+          ${{ steps.dep-report-check.outputs.exists == 'true' && steps.dep-summary.outputs.summary || '' }}
 
           This PR was automatically generated by the following workflow:
           ${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }}