feat: add step summary in code block

Signed-off-by: Jeremy Adams <jeremy@dagger.io>

action.yml

@@ -75,6 +75,8 @@ runs:
         INPUT_MODULE: ${{ inputs.module }}
       run: |
         tmpout=$(mktemp)
+        # Run the command and capture its output in `tmpout`
+        # while also displaying it in the logs
         cd ${{ inputs.workdir }} && { \
         DAGGER_CLOUD_TOKEN=${{ inputs.cloud-token }} \
         dagger \
@@ -83,8 +85,19 @@ runs:
         ${INPUT_MODULE:+-m $INPUT_MODULE} \
         ${{ inputs.args }}; } | tee "${tmpout}"
 
+        # Send the output to GITHUB_OUTPUT for further processing if needed
         (echo -n "stdout=" && cat "${tmpout}") >> "$GITHUB_OUTPUT"
 
+        # Append formatted output to GITHUB_STEP_SUMMARY
+        {
+          echo "### Dagger Output"
+          echo ""
+          echo "<pre><code>"
+          cat "${tmpout}"
+          echo "</code></pre>"
+          echo ""
+        } >> $GITHUB_STEP_SUMMARY
+
     - if: inputs.engine-stop == 'true'
       shell: bash
       run: |